Journal of Developmental Biology

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

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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

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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

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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

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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

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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

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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

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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

Viewed by 479

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

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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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J. Dev. Biol., Volume 13, Issue 2 (June 2025) – 9 articles

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