Search Results (10)

Background/Objectives: Acomys cahirinus exhibits more favorable cardiac remodeling after ischemic injury than Mus musculus, yet the molecular organization of the intact myocardium remains poorly characterized. This study aimed to identify baseline interspecies differences in the adult left ventricle, with particular emphasis on ventricular cardiomyocyte transcriptional states. Methods: Intact left ventricles from adult male A. cahirinus and M. musculus were analyzed by single-nucleus RNA sequencing using three biological samples per species. Cross-species integration was followed by cell type annotation, pseudobulk differential expression analysis, Augur-based assessment of interspecies separability, coexpression module analysis, and focused reintegration analysis of ventricular cardiomyocytes. Cardiomyocyte profiles were further compared with published embryonic and early postnatal M. musculus heart datasets. Results: Both species contained comparable major myocardial cell populations, whereas marked interspecies transcriptional differences persisted within individual cell types. Ventricular cardiomyocytes exhibited the largest number of differentially expressed genes and were classified into three transcriptional states: contractile, matrix-associated, and alternative. Adult A. cahirinus cardiomyocytes retained a mature cardiomyocyte phenotype but showed greater enrichment of developmental, morphogenetic, and Hippo-associated gene programs than adult M. musculus cardiomyocytes. Their transcriptional profile did not correspond to embryonic or early postnatal mouse states. The integrated atlas further identified interspecies differences in fibroblast-associated and extracellular matrix-related programs. Conclusions: The intact myocardium of A. cahirinus exhibits cell type-specific transcriptional differences relative to M. musculus. Ventricular cardiomyocytes display a distinct mature transcriptional configuration rather than a direct immature state, which may contribute to the favorable response of A. cahirinus to myocardial injury. Full article

Epicardial mesothelium plays a pivotal role in postinfarction cardiac repair by generating fibroblasts, producing extracellular matrix, and releasing paracrine mechanisms. However, interspecies differences have not been sufficiently studied, particularly in in vivo models of scar-free healing such as the African spiny mouse (Acomys cahirinus). This study aimed to compare the profibrotic response of epicardial mesothelial cells (MCs) from Acomys and C57BL/6 mice to hypoxic stress, a key factor in postinfarction recovery. We isolated epicardial MCs from the African spiny mouse (Acomys cahirinus), a species with documented cardiac regenerative capabilities, and from C57BL/6 laboratory mice. Using a CoCl₂-induced hypoxia model in vitro, we assessed cell viability, morphological changes, and expression of epithelial and fibroblast markers. In vivo, following experimental myocardial infarction (MI), we evaluated tissue hypoxia (pimonidazole adducts), epicardial activation (layer thickness, Wt1⁺ and TBX18⁺ progenitor cells), and collagen accumulation. The study was conducted using real-time PCR, Western blotting, immunohistochemical analysis and microscopic examination. In vitro, MCs from both species exhibited an epithelial-like phenotype under normoxic conditions, expressing E-cadherin and cytokeratin 18. Hypoxia (200 µM CoCl₂) induced a comparable response in both Acomys and C57BL/6 cells, characterized by a shift to a spindle-shaped, fibroblast-like morphology, decreased E-cadherin expression, and increased pro-collagen 1 and α-SMA expression. Following MI, both species exhibited similarly extensive hypoxic areas affecting the epicardial zone. Epicardial activation dynamics were comparable: from day 3 post-MI, epicardial thickness increased significantly, and Wt1⁺ and TBX18⁺ progenitor cells accumulated, peaking during the first week. Collagen accumulation in the epicardial region was similar between species, although the number of Wt1⁺ cells was higher in C57BL/6 on day 7. Despite the well-known superior regenerative capacity of spiny mice, epicardial MCs from Acomys and C57BL/6 demonstrated similar signs of profibrotic responses to hypoxic stimulation both in vitro and following MI. These findings suggest that species-specific regenerative outcomes may not be attributable to differential acute epicardial sensitivity to hypoxia, but rather to downstream mechanisms or additional factors influencing the cardiac repair process. This study provides the first characterization of Acomys epicardial MCs and establishes a foundation for further investigation of evolutionarily conserved and species-specific mechanisms of cardiac regeneration. Full article

Cutaneous leishmaniasis (CL) caused by Leishmania major is a zoonotic disease transmitted by phlebotomine sand flies. Identification of reservoir hosts is critical for understanding transmission and guiding control. While Psammomys obesus and Meriones shawi are recognized reservoirs in North Africa, the role of other rodents remains unclear. We experimentally assessed the reservoir potential of Acomys cahirinus seurati from southeastern Algeria. Animals were intradermally infected, and clinical signs and infectiousness to sand flies were monitored. Parasite persistence in skin and visceral tissues was measured by quantitative PCR. All animals developed localized, self-limiting lesions. Seven of sixteen individuals transmitted parasites to Phlebotomus papatasi between 10 and 25 weeks post-infection. Parasites were mostly restricted to the inoculation site, with limited dissemination to contralateral pinnae and hindpaws, and rare presence in spleen or liver. Notably, some animals were infectious without visible lesions, indicating that ulceration is not required for transmission. These findings show that A. cahirinus seurati can maintain L. major infection for up to 6 months and transmit parasites to sand flies, fulfilling key criteria of a reservoir host. Thus, this species may contribute to CL transmission in endemic foci lacking classical reservoirs, emphasizing the need to consider alternative rodent hosts in surveillance and control programs in North Africa. Full article

Recent discovery of menstruation in the Egyptian spiny mouse (Acomys cahirinus) highlighted this species as a feasible model for the study of menstrual cycle physiology. However, reports on active menstrual bleeding in this animal were contradictory, so we set out to reproduce major findings in the field. Using vaginal smear microscopy and occult blood assay, we have failed to detect menstrual bleeding in spiny mice from our colony at Lomonosov Moscow State University. Otherwise, we demonstrated appearance of well-defined decidual cells during the late secretory phase of the cycle that correlated with an increase in serum progesterone. Comparing the uteri of spiny mice from our colony vs. CD1 strain laboratory mice housed in the same animal unit, we have found several noteworthy features: (1) absence of endometrial glands, (2) higher volume of nerve fibers in the endometrium, and (3) spiral-like arteries in myometrium. Taking results of other groups into account, our results highlight putative diversity of menstrual cycles in spiny mice from different colonies and demonstrate important differences in uterus structure compared to M. musculus. Full article

This study investigates the adrenal gland structure and gene expression in Acomys cahirinus compared to Mus musculus, aiming to assess its relevance for human adrenal disease modeling. We identified a well-defined zona reticularis in Acomys, resembling the human adrenal cortex. Transcriptomic analysis revealed upregulation of key steroidogenic genes (Cyp17a1, Sult1e1, Hsd3b2, Defb18, Kiss1, H2-Ke6), with validation by qRT-PCR and CAGE-seq. The gene Nupl1 showed discordant results between RNA-seq and CAGE. Pathway analysis highlighted enrichment of steroidogenesis and adrenal metabolism. Notably, a GTEx-based comparison demonstrated that Acomys adrenal gene expression closely mirrors the expression in the human adrenal cortex, whereas Mus musculus samples diverged toward brain-specific signatures. These findings suggest that Acomys cahirinus represents a promising model for adrenal research, though further studies including single-cell transcriptomics and functional assays are warranted to fully establish its translational potential. Full article

The spiny mouse (Acomys species) is capable of scarless wound regeneration through largely yet unknown mechanisms. To investigate whether this capacity is related to peculiarities of the hemostatic system, we studied the blood of Acomys cahirinus in comparison to Mus musculus (Balb/c) to reveal differences in blood composition and clotting in both males and females. In response to surgical manipulations, blood clots formed in wounds of Acomys comprised a stronger hemostatic seal with reduced surgical bleeding in comparison with Balb/c. Acomys demonstrated notably shorter tail bleeding times and elevated clottable fibrinogen levels. Histological analysis revealed that clots from Acomys blood had densely packed fibrin-rich clots with pronounced fibrin segregation from erythrocytes. Acomys exhibited superior plasma clot stiffness as revealed with thromboelastography. The latter two characteristics are likely due to hyperfibrinogenemia. Light transmission platelet aggregometry demonstrated that ADP-induced platelet aggregates in Acomys males are stable, unlike the aggregates formed in the plasma of Balb/c undergoing progressive disaggregation over time. There were no apparent distinctions in platelet contractility and baseline expression of phosphatidylserine. Hematological profiling revealed a reduced erythrocytes count but increased mean corpuscular volume and hemoglobin content in Acomys. These results demonstrate the distinctive hemostatic potential of Acomys cahirinus, which may contribute to their remarkable regenerative capacity. Full article

Acomys cahirinus is a unique Rodentia species with several distinctive physiological traits, such as precocial development and remarkable regenerative abilities. These characteristics render A. cahirinus increasingly valuable for regenerative and developmental physiology studies. Despite this, the structure and postnatal development of the central nervous system in A. cahirinus have been inadequately explored, with only sporadic data available. This study is the first in a series of papers addressing these gaps. Our first objective was to characterize the structure of the main visual thalamic region, the lateral geniculate complex, using several neuronal markers (including Ca²⁺-binding proteins, glutamic acid decarboxylase enzyme, and non-phosphorylated domains of heavy-chain neurofilaments) to label populations of principal neurons and interneurons in adult and newborn A. cahirinus. As typically found in other rodents, we identified three subdivisions in the geniculate complex: the dorsal and ventral lateral geniculate nuclei (LGNd and LGNv) and the intergeniculate leaflet (IGL). Additionally, we characterized internal diversity in the LGN nuclei. The “shell” and “core” regions of the LGNd were identified using calretinin in adults and newborns. In adults, the inner and outer parts of the LGNv were identified using calbindin, calretinin, parvalbumin, GAD67, and SMI-32, whereas in newborns, calretinin and SMI-32 were employed for this purpose. Our findings revealed more pronounced developmental changes in LGNd compared to LGNv and IGL, suggesting that LGNd is less mature at birth and more influenced by visual experience. Full article

Bite wounds due to aggression in male laboratory mice (Mus musculus) are a major welfare concern, often leading to attrition, chronic activation of the innate immune system, and significant impacts on the experimental results derived from the use of these animals as models. Bite wounding within the home-cage of spiny mice (Acomys cahirinus)—a valuable research model for wound healing and menstruation—is poorly characterized. While we have anecdotally observed frequent bite wounding in Acomys, the frequency of aggression within the home-cage, the severity of the bite wounds, and the types of dominance structures remain unstudied. Here, we report that 46% of Acomys cages in our colony had at least one bite wound over the course of a year and that same-sex pairs fought in the home-cage 10% of the time during their dark/active phase. Both sexes inflicted wounds and frequently engaged in agonistic behaviors, even with stable dominance structures. We found that females inflicted less severe bite wounds in same-sex housing. Also, aged females in same-sex pairs were never observed fighting, and no bite wounds were observed in aged Acomys. These results suggest that we should consider whether bite wounding negatively impacts our experimental results since physical trauma is known to alter menstrual cycling and healing. Full article

A metabolite of leucine, ß-hydroxy-ß-methylbutyrate (HMB), used as a dietary supplement effects muscle tissue gain and bone tissue quality. Since there are no studies on the effects of HMB during pregnancy yet, the aim of the current study was to determine the effects of HMB supplementation during pregnancy on osteoporotic bone quality postpartum and post-lactation using spiny mice (Acomys cahirinus) as the animal models. The six-month-old dams were divided into four groups: pregnant and lactating controls, and pregnant and lactating HMB-treated (during the second trimester of pregnancy) females. The intensity of the immunoreaction of osteocalcin (OC), osteoprotegerin (OPG), bone morphogenetic protein 2 (BMP-2), tissue inhibitor of metalloproteinases 2 (TIMP-2), matrix metalloproteinase 8 and 13 (MMP-8 and MMP-13) and proteins involved in bone turnover, was measured in femoral trabecular and compact bone, as well as in the hyaline and epiphyseal cartilage of the femora. The analysis of the trabecular bone microarchitecture showed that the administration of HMB to pregnant females, by influencing the proteins responsible for bone cell activity and collagen remodeling, can provide protection from bone loss. Based on the results of the current study it can be assumed that HMB administration to pregnant females has a more positive impact on trabecular than compact bone. Full article

The aim of this study was to determine the effects of ß-hydroxy-ß-methylbutyrate (HMB) supplementation during pregnancy on postpartum bone tissue quality by assessing changes in trabecular and compact bone as well as in hyaline and epiphyseal cartilage. The experiment was carried out on adult 6-month-old female spiny mice (Acomys cahirinus) divided into three groups: pregnant control (PregCont), pregnant HMB-treated (supplemented with 0.02 g/kg b.w of HMB during the second trimester of pregnancy, PregHMB), and non-pregnant females (NonPreg). Cross-sectional area and cortical index of the femoral mid-shaft, stiffness, and Young modulus were significantly greater in the PregHMB group. Whole-bone mineral density was similar in all groups, and HMB supplementation increased trabecular number. Growth plate cartilage was the thinnest, while the articular cartilage was the thickest in the PregHMB group. HMB supplementation increased the content of proteoglycans in the articular cartilage and the percentage of immature collagen content in metaphyseal trabeculae and compact bone. In summary, dietary HMB supplementation during the second trimester of pregnancy intensifies bone metabolic processes and prevents bone loss during pregnancy. Full article