Journal of Developmental Biology

12 pages, 2254 KiB

Open AccessArticle

Evolution of the Jawed Vertebrate (Gnathostomata) Stomach Through Gene Repertoire Loss: Findings from Agastric Species

by Jackson Dann and Frank Grützner

J. Dev. Biol. 2025, 13(3), 27; https://doi.org/10.3390/jdb13030027 - 5 Aug 2025

The stomach has been a highly conserved organ throughout vertebrate evolution; however, there are now over 20 lineages composed of monotremes, lungfish and teleost fish displaying a secondary loss of stomach function and morphology. This “agastric phenotype” has evolved convergently and is typified [...] Read more.

The stomach has been a highly conserved organ throughout vertebrate evolution; however, there are now over 20 lineages composed of monotremes, lungfish and teleost fish displaying a secondary loss of stomach function and morphology. This “agastric phenotype” has evolved convergently and is typified by a loss of gastric glands and gastric acid secretion and a near-to-complete loss of storage capacity of the stomach. All agastric species have lost the genes for gastric enzymes (Pga and Pgc) and proton pump subunits (Atp4a and Atp4b), and gastrin (Gast) has been lost in monotremes. As a key gastric hormone, the conservation of gastrin has not yet been investigated in the lungfish or agastric teleosts, and it is unclear how the loss of gastrin affects the evolution and selection of the native receptor (Cckbr), gastrin-releasing peptide (Grp) and gastrin-releasing peptide receptor (Grpr) in vertebrates. Furthermore, there are still many genes implicated in gastric development and function which have yet to be associated with the agastric phenotype. We analysed the evolution, selection and conservation of the gastrin pathway and a novel gastric gene repertoire (Gkn1, Gkn2, Tff1, Tff2, Vsig1 and Anxa10) to determine the correlation with the agastric phenotype. We found that the loss of gastrin or its associated genes does not correlate with the agastric phenotype, and their conservation is due to multiple pleiotropic roles throughout vertebrate evolution. We found a loss of the gastric gene repertoire in the agastric phenotype, except in the echidna, which retained several genes (Gkn1, Tff2 and Vsig1). Our findings suggest that the gastrin physiological pathway evolved differently in pleiotropic roles throughout vertebrate evolution and support the convergent evolution of the agastric phenotype through shared independent gene-loss events. Full article

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18 pages, 3973 KiB

Open AccessArticle

Identification and Characterization of Static Craniofacial Defects in Pre-Metamorphic Xenopus laevis Tadpoles

by Emilie Jones, Jay Miguel Fonticella and Kelly A. McLaughlin

J. Dev. Biol. 2025, 13(3), 26; https://doi.org/10.3390/jdb13030026 - 25 Jul 2025

Abstract

Craniofacial development is a complex, highly conserved process involving multiple tissue types and molecular pathways, with perturbations resulting in congenital defects that often require invasive surgical interventions to correct. Remarkably, some species, such as Xenopus laevis, can correct some craniofacial abnormalities during [...] Read more.

Craniofacial development is a complex, highly conserved process involving multiple tissue types and molecular pathways, with perturbations resulting in congenital defects that often require invasive surgical interventions to correct. Remarkably, some species, such as Xenopus laevis, can correct some craniofacial abnormalities during pre-metamorphic stages through thyroid hormone-independent mechanisms. However, the full scope of factors mediating remodeling initiation and coordination remain unclear. This study explores the differential remodeling responses of craniofacial defects by comparing the effects of two pharmacological agents, thioridazine-hydrochloride (thio) and ivermectin (IVM), on craniofacial morphology in X. laevis. Thio-exposure reliably induces a craniofacial defect that can remodel in pre-metamorphic animals, while IVM induces a permanent, non-correcting phenotype. We examined developmental changes from feeding stages to hindlimb bud stages and mapped the effects of each agent on the patterning of craniofacial tissue types including: cartilage, muscle, and nerves. Our findings reveal that thio-induced craniofacial defects exhibit significant consistent remodeling, particularly in muscle, with gene expression analysis revealing upregulation of key remodeling genes, matrix metalloproteinases 1 and 13, as well as their regulator, prolactin.2. In contrast, IVM-induced defects show no significant remodeling, highlighting the importance of specific molecular and cellular factors in pre-metamorphic craniofacial correction. Additionally, unique neuronal profiles suggest a previously underappreciated role for the nervous system in tissue remodeling. This study provides novel insights into the molecular and cellular mechanisms underlying craniofacial defect remodeling and lays the groundwork for future investigations into tissue repair in vertebrates. Full article

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15 pages, 4716 KiB

Open AccessArticle

Deletion of Ptpmt1 by αMHC-Cre in Mice Results in Left Ventricular Non-Compaction

by Lei Huang, Maowu Cao, Xiangbin Zhu, Na Li, Can Huang, Kunfu Ouyang and Ze'e Chen

J. Dev. Biol. 2025, 13(3), 25; https://doi.org/10.3390/jdb13030025 - 18 Jul 2025

Abstract

Background: Left ventricular non-compaction cardiomyopathy (LVNC) is a congenital heart disease characterized by abnormal prenatal development of the left ventricle that has an aberrantly thick trabecular layer and a thinner compacted myocardial layer. However, the underlying molecular mechanisms of LVNC regulated by mitochondrial [...] Read more.

Background: Left ventricular non-compaction cardiomyopathy (LVNC) is a congenital heart disease characterized by abnormal prenatal development of the left ventricle that has an aberrantly thick trabecular layer and a thinner compacted myocardial layer. However, the underlying molecular mechanisms of LVNC regulated by mitochondrial phosphatase genes remain largely unresolved. Methods: We generated a mouse model with cardiac-specific deletion (CKO) of Ptpmt1, a type of mitochondrial phosphatase gene, using the αMHC-Cre, and investigated the effects of cardiac-specific Ptpmt1 deficiency on cardiac development. Morphological, histological, and immunofluorescent analyses were conducted in Ptpmt1 CKO and littermate controls. A transcriptional atlas was identified by RNA sequencing (RNA-seq) analysis. Results: We found that CKO mice were born at the Mendelian ratio with normal body weights. However, most of the CKO mice died within 24 h after birth, developing spontaneous ventricular tachycardia. Morphological and histological analysis further revealed that newborn CKO mice developed an LVNC phenotype, evidenced by a thicker trabecular layer and a thinner myocardium layer, when compared with the littermate control. We then examined the embryonic hearts and found that such an LVNC phenotype could also be observed in CKO hearts at E15.5 but not at E13.5. We also performed the EdU incorporation assay and demonstrated that cardiac cell proliferation in both myocardium and trabecular layers was significantly reduced in CKO hearts at E15.5, which is also consistent with the dysregulation of genes associated with heart development and cardiomyocyte proliferation in CKO hearts at the same stage, as revealed by both the transcriptome analysis and the quantitative real-time PCR. Deletion of Ptpmt1 in mouse cardiomyocytes also induced an increase in phosphorylated eIF2α and ATF4 levels, indicating a mitochondrial stress response in CKO hearts. Conclusions: Our results demonstrated that Ptpmt1 may play an essential role in regulating left ventricular compaction during mouse heart development. Full article

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20 pages, 3164 KiB

Open AccessReview

Is Hydra Axis Definition a Fluctuation-Based Process Picking Up External Cues?

by Mikhail A. Zhukovsky, Si-Eun Sung and Albrecht Ott

J. Dev. Biol. 2025, 13(3), 24; https://doi.org/10.3390/jdb13030024 - 17 Jul 2025

Abstract

Axis definition plays a key role in the establishment of animal body plans, both in normal development and regeneration. The cnidarian Hydra can re-establish its simple body plan when regenerating from a random cell aggregate or a sufficiently small tissue fragment. At the [...] Read more.

Axis definition plays a key role in the establishment of animal body plans, both in normal development and regeneration. The cnidarian Hydra can re-establish its simple body plan when regenerating from a random cell aggregate or a sufficiently small tissue fragment. At the beginning of regeneration, a hollow cellular spheroid forms, which then undergoes symmetry breaking and de novo body axis definition. In the past, we have published related work in a physics journal, which is difficult to read for scientists from other disciplines. Here, we review our work for readers not so familiar with this type of approach at a level that requires very little knowledge in mathematics. At the same time, we present a few aspects of Hydra biology that we believe to be linked to our work. These biological aspects may be of interest to physicists or members of related disciplines to better understand our approach. The proposed theoretical model is based on fluctuations of gene expression that are triggered by mechanical signaling, leading to increasingly large groups of cells acting in sync. With a single free parameter, the model quantitatively reproduces the experimentally observed expression pattern of the gene ks1, a marker for ‘head forming potential’. We observed that Hydra positions its axis as a function of a weak temperature gradient, but in a non-intuitive way. Supposing that a large fluctuation including ks1 expression is locked to define the head position, the model reproduces this behavior as well—without further changes. We explain why we believe that the proposed fluctuation-based symmetry breaking process agrees well with recent experimental findings where actin filament organization or anisotropic mechanical stimulation act as axis-positioning events. The model suggests that the Hydra spheroid exhibits huge sensitivity to external perturbations that will eventually position the axis. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Developmental Biology 2025)

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14 pages, 1891 KiB

Open AccessArticle

HP1-Mediated Silencing of the Doublesex1 Gene for Female Determination in the Crustacean Daphnia magna

by Junya Leim, Nikko Adhitama, Quang Dang Nong, Pijar Religia, Yasuhiko Kato and Hajime Watanabe

J. Dev. Biol. 2025, 13(3), 23; https://doi.org/10.3390/jdb13030023 - 3 Jul 2025

Abstract

The crustacean Daphnia magna produces genetically identical females and males by parthenogenesis. Males are produced in response to environmental cues including crowding and lack of food. For male development, the DM-domain containing transcription factor Doublesex1 (DSX1) is expressed spatiotemporally in male-specific traits and [...] Read more.

The crustacean Daphnia magna produces genetically identical females and males by parthenogenesis. Males are produced in response to environmental cues including crowding and lack of food. For male development, the DM-domain containing transcription factor Doublesex1 (DSX1) is expressed spatiotemporally in male-specific traits and orchestrates male trait formation in both somatic and gonadal tissues. However, it remains unknown how the dsx1 gene is silenced in females to avoid male trait development. Heterochromatin Protein 1 (HP1) plays a crucial role in epigenetic gene silencing during developmental processes. Here we report the identification of four HP1 orthologs in D. magna. None of these orthologs exhibited sexually dimorphic expression, and among them, HP1-1 was most abundantly expressed during embryogenesis. The knock-down of HP1-1 in female embryos led to the derepression of dsx1 in the male-specific traits, resulting in the development of male characteristics, such as the elongation of the first antennae. These results suggest that HP1-1 silences dsx1 for female development while environmental cues unlock this silencing to induce male production. We infer the HP1-dependent formation of a sex-specific chromatin structure on the dsx1 locus is a key process in the environmental sex determination of D. magna. Full article

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25 pages, 5014 KiB

Open AccessArticle

Investigating Psychopharmaceutical Effects on Early Vertebrate Development Using a Zebrafish Model System

by Nathan Zimmerman, Aaron Marta, Carly Baker, Zeljka Korade, Károly Mirnics and Annemarie Shibata

J. Dev. Biol. 2025, 13(3), 22; https://doi.org/10.3390/jdb13030022 - 27 Jun 2025

Abstract

Cholesterol homeostasis is necessary for normal vertebrate development. The disruption of cholesterol homeostasis can cause abnormal body and nervous system development and lead to dysfunctional behavior and increased mortality. Commonly prescribed psychopharmaceuticals can alter cholesterol synthesis and may disrupt early vertebrate development. A [...] Read more.

Cholesterol homeostasis is necessary for normal vertebrate development. The disruption of cholesterol homeostasis can cause abnormal body and nervous system development and lead to dysfunctional behavior and increased mortality. Commonly prescribed psychopharmaceuticals can alter cholesterol synthesis and may disrupt early vertebrate development. A high-throughput vertebrate zebrafish model system was used to test the hypothesis that exposure to psychopharmaceutical medications alters cholesterol biosynthesis and disrupts gene transcription, early whole-body and brain development, and nervous system function, resulting in abnormal behavior. Exposure to cariprazine, aripiprazole, trazodone, and AY9944 increased 7-dehydrocholesterol levels compared to vehicle-treated zebrafish. Significant differences in disease-associated gene expression, brain structure, and functional behaviors were observed in psychopharmaceutical and AY9944-treated zebrafish compared to controls. These data reveal that the high-throughput zebrafish model system can discern psychopharmaceutical effects on cholesterol synthesis, gene transcription, and key features of early vertebrate development that influences behavior. Full article

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14 pages, 1562 KiB

Open AccessArticle

Drosophila Males Differentially Express Small Proteins Regulating Stem Cell Division Frequency in Response to Mating

by Manashree S. Malpe, Leon F. McSwain, Heath M. Aston, Karl A. Kudyba, Chun Ng, Megan P. Wright and Cordula Schulz

J. Dev. Biol. 2025, 13(3), 21; https://doi.org/10.3390/jdb13030021 - 23 Jun 2025

Abstract

The germline stem cells (GSCs) in the male gonad of Drosophila can increase their division frequency in response to a demand for more sperm caused by repeated mating. However, the molecules and mechanisms regulating and mediating this response have yet to be fully [...] Read more.

The germline stem cells (GSCs) in the male gonad of Drosophila can increase their division frequency in response to a demand for more sperm caused by repeated mating. However, the molecules and mechanisms regulating and mediating this response have yet to be fully explored. Here, we present the results of a transcriptome analysis comparing expression from the testis tips from non-mated and mated males. An overlapping set of 18 differentially expressed genes (DEGs) from two independent wild-type (wt) strains revealed that the majority of the DEGs encode secreted proteins, which suggests roles for them in cell–cell interactions. Consistent with a role for secretion in regulating GSC divisions, knocking down Signal Recognition Particle (SRP) components within the germline cells using RNA Interference (RNAi), prevented the increase in GSC division frequency in response to mating. The major class of DEGs encodes polypeptides below the size of 250 amino acids, also known as small proteins. Upon reducing germline expression of small proteins, males no longer increased GSC division frequency after repeated mating. We hypothesize that mating induces cellular interactions via small proteins to ensure continued GSC divisions for the production of sperm. Full article

(This article belongs to the Special Issue Drosophila in Developmental Biology—Past, Present and Future)

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20 pages, 7139 KiB

Open AccessArticle

Cannabinoid Receptor 1 Regulates Zebrafish Renal Multiciliated Cell Development via cAMP Signaling

by Thanh Khoa Nguyen, Sophia Baker, Julienne Angtuaco, Liana Arceri, Samuel Kaczor, Bram Fitzsimonds, Matthew R. Hawkins and Rebecca A. Wingert

J. Dev. Biol. 2025, 13(2), 20; https://doi.org/10.3390/jdb13020020 - 17 Jun 2025

Abstract

Endocannabinoid signaling plays a significant role in neurogenesis and nervous system physiology, but its roles in the development of other tissues are just beginning to be appreciated. Previous reports have shown the presence of the key endocannabinoid receptor Cannabinoid receptor 1 (CB1 or [...] Read more.

Endocannabinoid signaling plays a significant role in neurogenesis and nervous system physiology, but its roles in the development of other tissues are just beginning to be appreciated. Previous reports have shown the presence of the key endocannabinoid receptor Cannabinoid receptor 1 (CB1 or Cnr1) in multiciliated (MCC) tissues and its upregulation in kidney diseases, yet the relationship between Cnr1 and renal MCC development is unknown. Here, we report that Cnr1 is essential for cilia development across tissues and regulates renal MCCs via cyclic AMP (cAMP) signaling during zebrafish embryogenesis. Using a combination of genetic and pharmacological studies, we found that the loss of function, agonism and antagonism of cnr1 all lead to reduced mature renal MCC populations. cnr1 deficiency also led to reduced cilia development across tissues, including the pronephros, ear, Kupffer’s vesicle (KV), and nasal placode. Interestingly, treatment with the cAMP activator Forskolin (FSK) restored renal MCC defects in agonist-treated embryos, suggesting that cnr1 mediates cAMP signaling in renal MCC development. Meanwhile, treatment with the cAMP inhibitor SQ-22536 alone or with cnr1 deficiency led to reduced MCC populations, suggesting that cnr1 also mediates renal MCC development independently of cAMP signaling. Our findings indicate that cnr1 has a critical role in controlling renal MCC development both via cAMP signaling and an independent pathway, further revealing implications for ciliopathies and renal diseases. Full article

(This article belongs to the Special Issue Feature Papers from Journal of Developmental Biology Reviewers)

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13 pages, 5576 KiB

Open AccessArticle

Ribosome Incorporation Transdifferentiates Chick Primary Cells and Induces Their Proliferation by Secreting Growth Factors

by Shota Inoue, Arif Istiaq, Anamika Datta, Mengxue Lu, Shintaro Nakayama, Kousei Takashi, Nobushige Nakajo, Shigehiko Tamura, Ikko Kawashima and Kunimasa Ohta

J. Dev. Biol. 2025, 13(2), 19; https://doi.org/10.3390/jdb13020019 - 1 Jun 2025

Abstract

Previously, we reported that mammalian cells, specifically human dermal fibroblasts (HDFs), could be transdifferentiated by lactic acid bacteria (LAB). Later, we observed that HDFs incorporated LAB-derived ribosomes, forming the ribosome-induced cell clusters (RICs) and transdifferentiating into cells derived from all three germ layers. [...] Read more.

Previously, we reported that mammalian cells, specifically human dermal fibroblasts (HDFs), could be transdifferentiated by lactic acid bacteria (LAB). Later, we observed that HDFs incorporated LAB-derived ribosomes, forming the ribosome-induced cell clusters (RICs) and transdifferentiating into cells derived from all three germ layers. Based on this insight, we hypothesized that incorporating ribosomes into non-mammalian cells could reveal the universality of this mechanism and open the door to commercial applications. Our current study demonstrates that ribosome incorporation can transdifferentiate chick primary muscle-derived cells (CMCs) into adipocytes, osteoblasts, and chondrocytes. Furthermore, the culture medium supernatant from ribosome-incorporated CMCs was found to significantly enhance CMC’s proliferation. RNA-seq analysis revealed that RICs-CMC exhibit increased expression of genes related to multi-lineage cell growth. In addition, we developed a novel technological shift in meat production—the “CulNet System”—which replicates organ interactions within mechanical systems for cell-cultured meat production. While significant efforts are still required to implement this technology in a cost-effective manner, we believe that combining the “CulNet System” with ribosome-incorporated multipotent cells that have prolonged culture capability could substantially improve the scalability and cost-effectiveness of cultured chicken meat production. This report highlights a promising approach for cell-culture-based meat production, offering a sustainable alternative to traditional methods. Full article

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12 pages, 1185 KiB

Open AccessArticle

Cornified Epithelial Teeth of Jawless Vertebrates Contain Proteins Similar to Keratin-Associated Proteins of Mammalian Skin Appendages

by Attila Placido Sachslehner, David A. D. Parry and Leopold Eckhart

J. Dev. Biol. 2025, 13(2), 18; https://doi.org/10.3390/jdb13020018 - 19 May 2025

Abstract

Keratins and keratin-associated proteins (KRTAPs) are the main components of mammalian nails and hair. Comparative genomics and gene expression studies have revealed that keratins are conserved in all vertebrates, whereas KRTAPs exist only in mammals. Recently, we found hair keratin-like cysteine-rich keratins in [...] Read more.

Keratins and keratin-associated proteins (KRTAPs) are the main components of mammalian nails and hair. Comparative genomics and gene expression studies have revealed that keratins are conserved in all vertebrates, whereas KRTAPs exist only in mammals. Recently, we found hair keratin-like cysteine-rich keratins in jawless vertebrates with confirmed expression in the cornified epithelial teeth of the sea lamprey (Petromyzon marinus). Here, we report that KRTAP-like proteins are also present in the horny teeth of the lamprey. Mass spectrometry-based proteomics identified proteins that share features with KRTAPs, such as high contents of cysteine and tyrosine residues, which support intermolecular interactions, and abundant glycine residues, which endow the proteins with flexibility. Genes encoding KRTAP-like proteins are arranged in a cluster in P. marinus, and the presence of at least one KRTAP-like protein is conserved in phylogenetically diverse species of lamprey, including Lampetra fluviatilis, Lethenteron reissneri, Geotria australis, and Mordacia mordax. The KRTAP-like genes of lampreys contain two exons, whereas mammalian KRTAPs have only a single exon. Although KRTAPs and KRTAP-like proteins are products of independent evolution, their common expression in cornified skin appendages suggests that they fulfill similar functions. Full article

(This article belongs to the Special Issue Feature Papers from Journal of Developmental Biology Reviewers)

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20 pages, 3146 KiB

Open AccessArticle

In Vitro Embryo Culture Impacts Heart Mitochondria in Male Adolescent Sheep

by Reza Amanollahi, Stacey L. Holman, Ashley S. Meakin, Monalisa Padhee, Kimberley J. Botting-Lawford, Song Zhang, Severence M. MacLaughlin, David O. Kleemann, Simon K. Walker, Jennifer M. Kelly, Skye R. Rudiger, I. Caroline McMillen, Michael D. Wiese, Mitchell C. Lock and Janna L. Morrison

J. Dev. Biol. 2025, 13(2), 17; https://doi.org/10.3390/jdb13020017 - 13 May 2025

Abstract

Assisted reproductive technology (ART)such as in vitro embryo culture (IVC), is widely used in human infertility treatments; however, its long-term effects on the cardiac health of offspring remain unclear. This study aimed to determine whether the effects of IVC on cardiac metabolism and [...] Read more.

Assisted reproductive technology (ART)such as in vitro embryo culture (IVC), is widely used in human infertility treatments; however, its long-term effects on the cardiac health of offspring remain unclear. This study aimed to determine whether the effects of IVC on cardiac metabolism and associated signaling pathways persist after birth into adolescence. Embryos were either transferred to an intermediate ewe (ET) or cultured in vitro in the absence (IVC) or presence of human serum (IVCHS) with methionine supplementation (IVCHS+M) for 6 days after mating. Naturally mated (NM) ewes were used as controls. Protein expression and hormone concentrations in the left ventricle (LV) were analyzed using Western blot and LC-MS/MS analyses, respectively. IVC was associated with sex-specific alterations in cardiac mitochondria, with males exhibiting reduced mitochondrial abundance. Cardiac protein expression of oxidative phosphorylation (OXPHOS) complexes 1 and 4 was reduced by IVC. Additionally, IVC reduced protein expression of PDK-4 and Mn-SOD in the IVCHS+M group, which may impact energy efficiency and defense against oxidative stress. These changes may predispose IVC offspring to cardiac oxidative stress and mitochondrial dysfunction, particularly in males. This study provides insights into the sex-dependent effects of IVC on cardiac health, emphasizing the importance of evaluating long-term cardiovascular risks associated with IVC protocols. Full article

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14 pages, 12403 KiB

Open AccessArticle

Dynamic Changes of Immunoreactive CD34, CD117, and CD41 Hematopoietic Stem Cells in Human Placentas of Different Gestational Ages

by Sanja Jovicic, Ivan R. Nikolic, Ljiljana Amidžić, Vesna Ljubojevic, Maja Barudzija and Ranko Skrbic

J. Dev. Biol. 2025, 13(2), 16; https://doi.org/10.3390/jdb13020016 - 9 May 2025

Abstract

Background: The process of prenatal hematopoiesis occurs in various anatomical locations, including the placenta. The placenta is not merely a temporary hematopoietic reservoir, but it is one of the key sites for the synthesis of hematopoietic stem cells (HSCs). This study aimed [...] Read more.

Background: The process of prenatal hematopoiesis occurs in various anatomical locations, including the placenta. The placenta is not merely a temporary hematopoietic reservoir, but it is one of the key sites for the synthesis of hematopoietic stem cells (HSCs). This study aimed to investigate the presence, distribution, and immunoprofiles of HSCs in the human placenta during different gestational periods. Materials and Methods: Placental samples of different gestational ages (first, second, and third trimesters) were analyzed using classical hematoxylin and eosin staining and immunohistochemical staining for CD34, CD117, and CD41 markers, with HSC quantification through numerical areal density (N_A). Results: Highly immunoreactive CD34 HSCs were present in placentas throughout gestation, while highly immunoreactive CD117 and CD41 HSCs were observed during the first two trimesters. In the first trimester, HSCs were found within the lumen of blood vessels and as individual cells in the mesenchyme of chorionic villi. With advancing gestation, the number of HSCs in the mesenchyme of chorionic villi increased. Conclusions: Immunoreactive CD34, CD117, and CD41 cells are present in significant proportions in various parts of the placenta throughout gestation, indicating that the placenta provides a substantial proportion of HSCs for hematopoiesis. Full article

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18 pages, 10507 KiB

Open AccessArticle

Probe Sequencing Analysis of Regenerating Lizard Tails Indicates Crosstalk Among Osteoclasts, Epidermal Cells, and Fibroblasts

by Darian J. Gamble, Samantha Lopez, Melody Yazdi, Toni Castro-Torres and Thomas P. Lozito

J. Dev. Biol. 2025, 13(2), 15; https://doi.org/10.3390/jdb13020015 - 3 May 2025

Abstract

Lizards are distinguished as the only amniotes, and closest relatives of mammals, capable of multilineage epimorphic regeneration. Tail blastemas of green anole lizards (Anolis carolinensis) consist of col3a1⁺ fibroblastic connective tissue cells enclosed in krt5⁺ wound epidermis (WE), both [...] Read more.

Lizards are distinguished as the only amniotes, and closest relatives of mammals, capable of multilineage epimorphic regeneration. Tail blastemas of green anole lizards (Anolis carolinensis) consist of col3a1⁺ fibroblastic connective tissue cells enclosed in krt5⁺ wound epidermis (WE), both of which are required for regeneration. Blastema and WE formation are known to be closely associated with phagocytic cell populations, including macrophages and osteoclasts. However, it remains unclear what specific phagocytic cell types are required to stimulate regeneration. Here, we explicitly assess the roles of osteoclast activity during blastema and WE formation in regenerating lizard tails. First, probe sequencing was performed at regenerative timepoints on fibroblasts isolated based on col3a1 expression toward establishing pathways involved in stimulating blastema formation and subsequent tail regrowth. Next, treatments with osteoclast inhibitor zoledronic acid (ZA) were used to assess the roles of osteoclast activity in lizard tail regeneration and fibroblast signaling. ZA treatment stunted lizard tail regrowth, suggesting osteoclast activity was required for blastema formation and regeneration. Transcriptomic profiling of fibroblasts isolated from ZA-treated and control lizards linked inhibition of osteoclast activity with limitations in fibroblasts to form pro-regenerative extracellular matrix and support WE formation. These results suggest that crosstalk between osteoclasts and fibroblasts regulates blastema and WE formation during lizard tail regeneration. Full article

(This article belongs to the Special Issue Skin Wound Healing and Regeneration in Vertebrates)

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12 pages, 907 KiB

Open AccessArticle

Follicular Fluid from Cows That Express Estrus During a Fixed-Time Artificial Insemination Protocol Promotes Blastocyst Development

by Audra W. Harl, Verónica M. Negrón-Pérez, Jacob W. Stewart, George A. Perry, Alan D. Ealy and Michelle L. Rhoads

J. Dev. Biol. 2025, 13(2), 14; https://doi.org/10.3390/jdb13020014 - 25 Apr 2025

Abstract

It is not yet understood why cows that exhibit estrus and ovulate are more likely to become pregnant than those that ovulate but do not exhibit estrus during a fixed-time artificial insemination (FTAI) protocol. The objective of this work was to determine whether [...] Read more.

It is not yet understood why cows that exhibit estrus and ovulate are more likely to become pregnant than those that ovulate but do not exhibit estrus during a fixed-time artificial insemination (FTAI) protocol. The objective of this work was to determine whether the follicular fluid from cows that exhibit estrus contributes to the increased likelihood of pregnancy. Lactating crossbred cows were subjected to an FTAI estrous synchronization protocol. Estrous behavior was observed and recorded prior to transvaginal follicle aspiration from cows that did (estrus, n = 7) or did not exhibit estrus (non-estrus, n = 6). Follicular fluid (25%) was then added to in vitro maturation media for the maturation of oocytes (n = 1489) from slaughterhouse ovaries. Cleavage rates were not affected by the estrous status of the cows from which the follicular fluid was collected. Blastocyst rates, however, were greater following maturation in the presence of follicular fluid from estrus cows compared to non-estrus cows (p ≤ 0.01). This difference in blastocyst rates was not related to blastocyst cell numbers (inner cell mass, trophoblast, and total), as they did not differ between estrus and non-estrus animals. This study demonstrates that the follicular fluid, and thus, the follicular environment just prior to ovulation does indeed contribute to improved pregnancy rates following FTAI. Full article

(This article belongs to the Special Issue Feature Papers in Journal of Developmental Biology 2025)

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16 pages, 1521 KiB

Open AccessPerspective

Origins of Aortic Coarctation: A Vascular Smooth Muscle Compartment Boundary Model

by Christina L. Greene, Geoffrey Traeger, Akshay Venkatesh, David Han and Mark W. Majesky

J. Dev. Biol. 2025, 13(2), 13; https://doi.org/10.3390/jdb13020013 - 18 Apr 2025

Abstract

Compartment boundaries divide the embryo into segments with distinct fates and functions. In the vascular system, compartment boundaries organize endothelial cells into arteries, capillaries, and veins that are the fundamental units of a circulatory network. For vascular smooth muscle cells (SMCs), such boundaries [...] Read more.

Compartment boundaries divide the embryo into segments with distinct fates and functions. In the vascular system, compartment boundaries organize endothelial cells into arteries, capillaries, and veins that are the fundamental units of a circulatory network. For vascular smooth muscle cells (SMCs), such boundaries produce mosaic patterns of investment based on embryonic origins with important implications for the non-uniform distribution of vascular disease later in life. The morphogenesis of blood vessels requires vascular cell movements within compartments as highly-sensitive responses to changes in fluid flow shear stress and wall strain. These movements underline the remodeling of primitive plexuses, expansion of lumen diameters, regression of unused vessels, and building of multilayered artery walls. Although the loss of endothelial compartment boundaries can produce arterial–venous malformations, little is known about the consequences of mislocalization or the failure to form SMC-origin-specific boundaries during vascular development. We propose that the failure to establish a normal compartment boundary between cardiac neural-crest-derived SMCs of the 6th pharyngeal arch artery (future ductus arteriosus) and paraxial-mesoderm-derived SMCs of the dorsal aorta in mid-gestation embryos leads to aortic coarctation observed at birth. This model raises new questions about the effects of fluid flow dynamics on SMC investment and the formation of SMC compartment borders during pharyngeal arch artery remodeling and vascular development. Full article

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15 pages, 14856 KiB

Open AccessArticle

Activation of Marck-like Genes and Proteins During Initial Phases of Regeneration in the Amputated Tail and Limb of the Lizard Podarcis muralis

by Lorenzo Alibardi

J. Dev. Biol. 2025, 13(2), 12; https://doi.org/10.3390/jdb13020012 - 14 Apr 2025

Abstract

Molecules involved in the activation of regeneration in reptiles are almost unknown. MARCK-like proteins are indicated to activate regeneration in some amphibians and fish, and it would be important to know whether this is a general process also present in other vertebrates. To [...] Read more.

Molecules involved in the activation of regeneration in reptiles are almost unknown. MARCK-like proteins are indicated to activate regeneration in some amphibians and fish, and it would be important to know whether this is a general process also present in other vertebrates. To address this problem, the present study reports the immunolocalization of a MARCK-like protein in injured tissues of a lizard. Bioinformatics and immunofluorescence after 5BrdU administration, and detection of MARCK-like proteins, have been performed on regenerating tail and limb of the lizard Podarcis muralis. Transcriptome data indicate up-regulation of MARCKS and MARCK-like1 expression in the initial regenerating tail and limb blastemas, supporting their involvement in the activation of regeneration in both appendages. Immunofluorescence for 5BrdU shows numerous proliferating cells in the blastemas of both appendages. Immunolocalization of a MARCK-like protein, using an antibody generated against a homologous protein from the axolotl, shows that the wound epidermis, nerves, and myotubes accumulate most of the protein in the limb and tail. MARCK-like immunolabeling is also detected in the regenerating spinal cord of the tail. The study indicates that, although the limb later turns into a scar, the MARCK-like protein is also up-regulated in this appendage, like in the regenerating tail. These results indicate that the initial reaction to an injury in lizards, an amniote representative, includes some triggering processes observed in amphibians and fish (anamniotes), with the activation of MARCK-like genes and proteins. This suggests that a MARCK-like-dependant mechanism for tissue repair is likely activated during the initial phases of vertebrate wound healing. Full article

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18 pages, 1690 KiB

Open AccessReview

Super-Enhancers in Placental Development and Diseases

by Gracy X. Rosario, Samuel Brown, Subhradip Karmakar, Mohammad A. Karim Rumi and Nihar R. Nayak

J. Dev. Biol. 2025, 13(2), 11; https://doi.org/10.3390/jdb13020011 - 9 Apr 2025

Abstract

The proliferation of trophoblast stem (TS) cells and their differentiation into multiple lineages are pivotal for placental development and functions. Various transcription factors (TFs), such as CDX2, EOMES, GATA3, TFAP2C, and TEAD4, along with their binding sites and cis-regulatory elements, have been studied [...] Read more.

The proliferation of trophoblast stem (TS) cells and their differentiation into multiple lineages are pivotal for placental development and functions. Various transcription factors (TFs), such as CDX2, EOMES, GATA3, TFAP2C, and TEAD4, along with their binding sites and cis-regulatory elements, have been studied for their roles in trophoblast cells. While previous studies have primarily focused on individual enhancer regions in trophoblast development and differentiation, recent attention has shifted towards investigating the role of super-enhancers (SEs) in different trophoblast cell lineages. SEs are clusters of regulatory elements enriched with transcriptional regulators, forming complex gene regulatory networks via differential binding patterns and the synchronized stimulation of multiple target genes. Although the exact role of SEs remains unclear, they are commonly found near master regulator genes for specific cell types and are implicated in the transcriptional regulation of tissue-specific stem cells and lineage determination. Additionally, super-enhancers play a crucial role in regulating cellular growth and differentiation in both normal development and disease pathologies. This review summarizes recent advances on SEs’ role in placental development and the pathophysiology of placental diseases, emphasizing the potential for identifying SE-driven networks in the placenta to provide valuable insights for developing therapeutic strategies to address placental dysfunctions. Full article

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15 pages, 3888 KiB

Open AccessArticle

Wound-Induced Regeneration in Feather Follicles: A Stepwise Strategy to Regenerate Stem Cells

by Ting-Xin Jiang, Ping Wu, Ang Li, Randall B. Widelitz and Cheng-Ming Chuong

J. Dev. Biol. 2025, 13(2), 10; https://doi.org/10.3390/jdb13020010 - 27 Mar 2025

Abstract

How to elicit and harness regeneration is a major issue in wound healing. Skin injury in most amniotes leads to repair rather than regeneration, except in hair and feathers. Feather follicles are unique organs that undergo physiological cyclic renewal, supported by a dynamic [...] Read more.

How to elicit and harness regeneration is a major issue in wound healing. Skin injury in most amniotes leads to repair rather than regeneration, except in hair and feathers. Feather follicles are unique organs that undergo physiological cyclic renewal, supported by a dynamic stem cell niche. During normal feather cycling, growth-phase proximal follicle collar bulge stem cells adopt a ring configuration. At the resting and initiation phases, these stem cells descend to the dermal papilla to form papillary ectoderm and ascend to the proximal follicle in a new growth phase. Plucking resting-phase feathers accelerates papillary ectoderm cell activation. Plucking growth-phase feathers depletes collar bulge stem cells; however, a blastema reforms the collar bulge stem cells, expressing KRT15, LGR6, Sox9, integrin-α6, and tenascin C. Removing the follicle base and dermal papilla prevents feather regeneration. Yet, transplanting an exogenous dermal papilla to the follicle base can induce re-epithelialization from the lower follicle sheath, followed by feather regeneration. Thus, there is a stepwise regenerative strategy using stem cells located in the collar bulge, papillary ectoderm, and de-differentiated lower follicle sheath to generate new feathers after different levels of injuries. This adaptable regenerative mechanism is based on the hierarchy of stem cell regenerative capacity and underscores the remarkable resilience of feather follicle regenerative abilities. Full article

(This article belongs to the Special Issue Skin Wound Healing and Regeneration in Vertebrates)

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14 pages, 3521 KiB

Open AccessArticle

Varanid Teeth Asymmetry and Correlation to Body Size

by Guy Sion and Domenic C. D’Amore

J. Dev. Biol. 2025, 13(1), 9; https://doi.org/10.3390/jdb13010009 - 10 Mar 2025

Abstract

Stressors such as injuries, embryonic instability during development, and higher levels of stress hormones such as testosterone can result in increases in fluctuating asymmetry in reptiles and other vertebrates. Digit asymmetry, digit ratio variability, and skull trait asymmetry such as eye and jaw [...] Read more.

Stressors such as injuries, embryonic instability during development, and higher levels of stress hormones such as testosterone can result in increases in fluctuating asymmetry in reptiles and other vertebrates. Digit asymmetry, digit ratio variability, and skull trait asymmetry such as eye and jaw size have been correlated with stress level in both snakes and lizards. Teeth asymmetry has also been used as a biomarker for stress and brain laterality. Body size is correlated with many potential stressors, yet there has been little research on how body size in reptiles relates to asymmetry. We investigate teeth asymmetry within the lizard family Varanidae, a clade with a diverse range of sizes consisting of the largest living lizard, Varanus komodoensis. Using a landmark/semi-landmark analysis, we derived Centroid Size for 671 pairs of teeth from 13 varanid species, and asymmetry was derived for each pair. Right-biased asymmetry was significantly greater in the upper tooth row, but breaking up tooth positions into further sections did not yield a significant difference. We found a significant positive linear correlation between body size and right-biased teeth directional asymmetry within Varanus, but only when excluding V. komodoensis. This significant correlation may result from fewer potential predators and more potential food items, thus resulting in less overall stress. When analyzed separately, V. komodoensis individuals with <180 mm head length demonstrated a positive, yet non-significant, trend along a similar trajectory to their congenerics with a high goodness of fit. On the other hand, individuals > 180 mm showed a high degree of scatter, with several specimens having pronounced left-biased asymmetry. We suspect that this dramatic change was due to a combination of ontogenetic niche shift, bigger home ranges, a greater susceptibility to negative anthropogenic influences, and/or a male bias in the bigger specimens sampled, but a larger sample size is required to determine if there is statistical significance in these intra-specific trends. Body asymmetry can reflect brain laterality, which may be a potential driver for the teeth asymmetry seen here. Full article

(This article belongs to the Special Issue Feature Papers from Journal of Developmental Biology Reviewers)

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