Regulation Of Differentiation Research Articles

Knockdown of LAP2α inhibits adipogenesis of human adipose-derived stem cells and ameliorates high-fat diet-induced obesity.

Adipogenesis, a pivotal cellular process involving the differentiation of mesenchymal stem cells (MSCs) to mature adipocytes, plays a significant role in various physiological functions. Dysregulation of adipogenesis is implicated in conditions such as obesity. However, the complete molecular understanding of adipogenesis remains elusive. This study aimed to uncover the novel role of lamina-associated polypeptide 2 alpha (LAP2α) in human adipose-derived stem cells (hASCs) adipogenesis and its impact on high-fat diet (HFD)-induced obesity and associated metabolic disturbances. LAP2α expression was assessed during the adipogenic differentiation of hASCs using RT-qPCR and western blotting. The functional role of LAP2α in adipogenesis was explored both invitro and invivo through loss- and gain-of-function studies. Moreover, mice with HFD-induced obesity received lentivirus injection to assess the effect of LAP2α knockdown on fat accumulation. Molecular mechanisms underlying LAP2α in adipogenic differentiation were investigated using RT-qPCR, Western blotting, immunofluorescence staining, and Oil Red O staining. LAP2α expression was upregulated during hASCs adipogenic differentiation. LAP2α knockdown hindered adipogenesis, while LAP2α overexpression promoted adipogenic differentiation. Notably, LAP2α deficiency resisted HFD-induced obesity, improved glucose intolerance, mitigated insulin resistance, and prevented fatty liver development. Mechanistically, LAP2α knockdown attenuated signal transducer and activator of transcription 3 (STAT3) activation by reducing the protein level of phosphorylated STAT3. A STAT3 activator (Colivelin) counteracted the negative impact of LAP2α deficiency on hASCs adipogenic differentiation. Taken together, our current study established LAP2α as a crucial regulator of hASCs adipogenic differentiation, unveiling a new therapeutic target for obesity prevention.

Single-Cell Profiling Reveals the Impact of Genetic Alterations on the Differentiation of Inflammation-Induced Murine Colon Tumors

Genetic mutations and chronic inflammation of the colon contribute to the development of colorectal cancer (CRC). Using a murine model of inflammation-induced colon tumorigenesis, we determined how genetic mutations alter colon tumor cell differentiation. Inflammation induced by enterotoxigenic Bacteroides fragilis (ETBF) colonization of multiple intestinal neoplasia (MinApcΔ716/+) mice triggers loss of heterozygosity of Apc causing colon tumor formation. Here, we report that the addition of BRAFV600E mutation (BRAFF-V600ELgr5tm1(Cre/ERT2)CleMinApcΔ716/+, BLM) or knocking out Msh2 (Msh2LoxP/LoxPVil1-creMinApcΔ716/+, MSH2KO) in the Min model altered colon tumor differentiation. Using single-cell RNA sequencing, we uncovered the differences between BLM, Min, and MSH2KO tumors at a single-cell resolution. BLM tumors showed an increase in differentiated tumor epithelial cell lineages and a reduction in the tumor stem cell population. Interestingly, the tumor stem cell population of BLM tumors had revival colon stem cell characteristics with low WNT signaling and an increase in RevCSC marker gene expression. In contrast, MSH2KO tumors were characterized by an increased tumor stem cell population that had higher WNT signaling activity compared to Min tumors. Furthermore, overall BLM tumors had higher expression of transcription factors that drive differentiation, such as Cdx2, than Min tumors. Using RNA velocity, we identified additional potential regulators of BLM tumor differentiation such as NDRG1. The role of CDX2 and NDRG1 as putative regulators for BLM tumor cell differentiation was verified using organoids derived from BLM tumors. Our results demonstrate the critical connections between genetic mutations and cell differentiation in inflammation-induced colon tumorigenesis. Understanding such roles will deepen our understanding of inflammation-associated colon cancer.

Suppression of TNF-α activity by immobilization rescues Mkx expression and attenuates tendon ossification in a mouse Achilles tenotomy model.

Traumatic heterotopic ossification is a condition in which extraskeletal bone formation occurs in soft tissues after injury. It most commonly occurs in patients who had major orthopedic surgery and in those with severe extremity injuries. The lesion causes local pain and can impair motor function of the affected limb, but there is currently no established prophylaxis or treatment for this condition. In this study, we show that immobilization at an early stage of the inflammatory response after injury can attenuate ossification formation in a murine Achilles tenotomy model. Gene expression analysis revealed a decrease in the expression of Tnf and an increase in the expression of Mkx, which encodes one of the master regulators of tendon differentiation, Mohawk. Notably, we found that TNF-α suppressed the expression of Mkx transcripts and accelerated the osteogenic differentiation of tendon-derived mesenchymal stem cells (MSCs), suggesting that TNF-α acts as a negative regulator of Mkx transcription. Consistent with these findings, pharmaceutical inhibition of TNF-α increased the expression of Mkx transcripts and suppressed bone formation in this mouse model. These findings reveal the previously unrecognized involvement of TNF-α in regulating tendon MSC fate through suppression of Mkx expression and suggest that TNF-α is a potential target for preventing traumatic heterotopic ossification.

Elucidating epigenetic mechanisms governing odontogenic differentiation in dental pulp stem cells: an in-depth exploration

Epigenetics refers to the mechanisms such as DNA methylation and histone modification that influence gene expression without altering the DNA sequence. These epigenetic modifications can regulate gene transcription, splicing, and stability, thereby impacting cell differentiation, development, and disease occurrence. The formation of dentin is intrinsically linked to the odontogenic differentiation of dental pulp stem cells (DPSCs), which are recognized as the optimal cell source for dentin-pulp regeneration due to their varied odontogenic potential, strong proliferative and angiogenic characteristics, and ready accessibility Numerous studies have demonstrated the critical role of epigenetic regulation in DPSCs differentiation into specific cell types. This review thus provides a comprehensive review of the mechanisms by which epigenetic regulation controls the odontogenesis fate of DPSCs.

KLF9 regulates osteogenic differentiation of mesenchymal stem cells.

Osteoporosis is a progressive skeletal disease which is characterized by reduced bone mass and degradation of bone microstructure. Mesenchymal stem cells (MSCs) have the potential to inhibit osteoporosis since they are multipotent stem cells that can differentiate into multiple types of cells including osteoblasts. Hence the mechanism of osteogenic differentiation of MSCs deserves comprehensive study. Here we report that KLF9 is a novel regulator in osteogenic differentiation of MSCs. We observed that depletion of KLF9 can largely compromise the osteogenic differentiation ability of MSCs. In addition, we revealed that inhibition of the PI3K-Akt pathway could also affect osteogenic differentiation since KLF9 depletion inhibits PI3K expression. Finally, we discovered that KLF9 expression can be induced by dexamethasone which is an essential component in osteogenic induction medium. Taken together, our study provides new insights into the regulatory role of KLF9 in osteogenic differentiation of MSCs.

Identification of related-genes of T cells in lung tissue of chronic obstructive pulmonary disease based on bioinformatics and experimental validation

T cells are one of the main cell types shaping the immune microenvironment in chronic obstructive pulmonary disease (COPD). They persist andplay cytotoxic roles. The purpose of this study aimed to explore the potential related-genes of T cells in lung tissue of COPD. Chip data GSE38974 and single_celldata GSE196638 were downloaded from the GEO database. Difference analyses and WGCNA of GSE38974 were performed to identify DEGs and the modules most associated with the COPD phenotype. Various cell subsets were obtained by GSE196638, and DEGs of T cells were further identified. GO, GSEA and KEGG enrichment analyses were conducted to explore the biological functions and regulatory signaling pathways of the DEGs and DEGs of T cells. The intersection of the DEGs, module genes and DEGs of T cells was assessed to acquire related-genes of T cells. The mRNA and protein expression levels of related-genes ofT cells were verified in lung tissue of mouse with emphysema model. Based on GSE38974 difference analysis, 3811 DEGs were obtained. The results of WGCNA showed that the red module had the highest correlation coefficient with the COPD phenotype. GSE196638 analysis identified 124 DEGs of T cells. The GO, GSEAand KEGG enrichment analyses mainly identified genes involved in I-kappaB kinase/NF-kappaB signaling, receptor signaling pathway via STAT, regulationof CD4-positive cells, regulation of T-helper cell differentiation, chemokine signaling pathway, Toll-likereceptor signaling pathway, CD8-positive cells, alpha–beta T cell differentiation, MAPK signaling pathway and Th17 cell differentiation. The DEGs, genes of the red module and DEGs of T cells were overlapped to acquire FOXO1 and DDX17. The results of RT-qPCR and Western Blot indicate that the mRNA and protein expression levels of FOXO1 and DDX17 in lung tissue of emphysema mice were significantly higher compared with those in air-exposed mice. FOXO1 as well as DDX17 may be related-genesof T cells in lung tissue of patient with COPD, and their participation in the biological processes of different signaling pathways may inspire further COPD research.

Regulation of YAP and Wnt signaling by the endosomal protein MAMDC4.

Maintenance of the intestinal epithelium requires constant self-renewal and regeneration. Tight regulation of proliferation and differentiation of intestinal stem cells within the crypt region is critical to maintaining homeostasis. The transcriptional co-factors β-catenin and YAP are required for proliferation during normal homeostasis as well as intestinal regeneration after injury: aberrant signaling activity results in over proliferation and tumorigenesis. Although both YAP and β-catenin activity are controlled along canonical pathways, it is becoming increasingly clear that non-canonical regulation of these transcriptional regulators plays a role in fine tuning their activity. We have shown previously that MAMDC4 (Endotubin, AEGP), an integral membrane protein present in endosomes, regulates both YAP and β-catenin activity in kidney epithelial cells and in the developing intestinal epithelium. Here we show that MAMDC4 interacts with members of the signalosome and mediates cross-talk between YAP and β-catenin. Interestingly, this cross-talk occurs through a non-canonical pathway involving interactions between AMOT:YAP and AMOT:β-catenin.

#1479 Single nucleus RNA-sequencing indicates functional heterogeneity of renal endothelial cells in chronic kidney disease

Abstract Background and Aims The burden of cardiovascular disease (CVD) in patients with chronic kidney disease (CKD) remains very high. Endothelial cell (EC) dysfunction is an important key player in the initiation and progression of both pathologies. More importantly, endothelial dysfunction occurs early in both disease courses and is potentially reversible, making it a promising target for effective preventive strategies. Recently, accumulating single-cell RNA sequencing-based evidence has highlighted EC heterogeneity in different pathophysiological contexts. However, while biological processes such as systemic inflammation, oxidative stress fibrosis are being defined as comm EC in CKD and CVD, a comprehensive understanding of at single-cell resolution is lacking. Here, we characterized renal EC subpopulations by single-nucleus RNA sequencing (snRNA-seq) to investigate alterations in CKD patients healthy controls and identify potential drivers of EC dysfunction in CKD. Method Droplet-based snRNA-seq (10X Genomics Chromium) was performed on cryopreserved kidney biopsy cores from 6 human patients with CKD (eGFR < 45 mL/min/1.73 m2) and 3 healthy controls. CKD patients included 2 patients with primary focal segmental glomerulosclerosis (FSGS) and 4 with secondary/maladaptive FSGS (2 patients with diabetes mellitus, 2 female patients in total); all patients had a Framingham 10-year cardiovascular risk score > 20, but no established CVD. Healthy control samples were pre-perfusion biopsies from patients undergoing living kidney donation (including 2 female patients). EC subclusters were annotated based on the expression of canonical EC marker genes. Differential gene expression analysis for patient samples vs. controls included all ECs and DEGs were filtered for log2FC > 0.25 or < −0.25 and adjusted P-value of < .05. Gene set enrichment analysis (GSEA) on the identified DEGs was performed using GO terms. Results A total of 4 081 ECs were present in the dataset, consisting of 5 EC subtypes in both the patient and control cohorts (Panel A). DEGs in CKD patients vs. controls included upregulated genes related to organogenesis and cell differentiation (MEF2C, MEIS2), vascular development (FLRT2), and angiogenesis regulators (VEGFC, PRCP, HDAC9) (Panel B). Notably, VEGFC and FLRT2, are involved in directing EC motility and vascular patterning. In accordance, GSEA showed enrichment for GO biological processes related to vascular endothelial growth factor signaling pathway, endothelial cell differentiation, endothelial development, regulation of angiogenesis, and endothelial cell migration (Panel C). This suggests a potential link between these genes and aberrant angiogenesis, analogous to previous findings in diabetic nephropathy. Some but not all of these changes were also reported for renal ECs of early diabetic nephropathy patients. Of note, the majority of patients studied in our cohort were non-diabetic, warranting further investigation into renal endothelial cell transcriptional alterations that are general to renal disease or specific to particular renal conditions such as diabetic nephropathy. Differential gene expression and GSEA analysis of the EC subclusters in CKD indicated involvement of the peritubular capillary and ascending vasa recta ECs in EC migration / angiogenesis-related responses, overlapping with the overall analysis described above. Glomerular capillary ECs showed upregulation of immune-related genes and processes, reflecting the inflammatory status of the kidney disease. Conclusion snRNA-seq analysis revealed heterogeneity and subtype-specific gene expression alterations of renal ECs from CKD patients compared to healthy controls. Differential functions include enhanced angiogenic (potentially compensatory) and immune-related responses. These findings suggest that specific biological functions may direct different roles of the renal EC subtypes in CKD and will be further validated for their cluster-specificity and for their therapeutic relevance.

Transcriptomic Analyses Reveal the Effects of Walnut Kernel Cake on Adipose Deposition in Pigs

With the rising cost of animal feed protein, finding affordable and effective substitutes is crucial. Walnut kernel cake, a polyphenol-, fiber-, protein- and fat-rich byproduct of walnut oil extraction, has been underexplored as a potential protein replacement in pig feed. In this study, we found that feeding large Diqing Tibetan pigs walnut kernel cake promoted adipose deposition and improved pork quality during pig growth. Transcriptome analysis revealed the upregulation of genes ANGPTL8, CCNP, ETV4, and TRIB3, associated with adipose deposition. Pathway analysis highlighted enrichment in adipose deposition-related pathways, including PPAR, insulin, PI3K-Akt, Wnt, and MAPK signaling. Further analysis identified DEGs (differentially expressed genes) positively correlated with adipose-related traits, such as PER2 and PTGES. Single-cell transcriptome data pointed to the specific expression of CD248 and PTGES in adipocyte progenitor/stem cells (APSCs), pivotal for adipocyte differentiation and adipose deposition regulation. This study demonstrates walnut kernel cake’s potential to substitute soybean cake in pig feed, providing high-quality protein and promoting adipose deposition. It offers insights into feed protein replacement, human functional food, fat metabolism, and related diseases, with marker genes and pathways supporting pig breeding and pork quality improvement.

Chaperone-Mediated Autophagy in Brain Injury: A Double-Edged Sword with Therapeutic Potentials.

Autophagy is an intracellular recycling process that maintains cellular homeostasis by degrading excess or defective macromolecules and organelles. Chaperone-mediated autophagy (CMA) is a highly selective form of autophagy in which a substrate containing a KFERQ-like motif is recognized by a chaperone protein, delivered to the lysosomal membrane, and then translocated to the lysosome for degradation with the assistance of lysosomal membrane protein 2A. Normal CMA activity is involved in the regulation of cellular proteostasis, metabolism, differentiation, and survival. CMA dysfunction disturbs cellular homeostasis and directly participates in the pathogenesis of human diseases. Previous investigations on CMA in the central nervous system have primarily focus on neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease. Recently, mounting evidence suggested that brain injuries involve a wider range of types and severities, making the involvement of CMA in the bidirectional processes of damage and repair even more crucial. In this review, we summarize the basic processes of CMA and its associated regulatory mechanisms and highlight the critical role of CMA in brain injury such as cerebral ischemia, traumatic brain injury, and other specific brain injuries. We also discuss the potential of CMA as a therapeutic target to treat brain injury and provide valuable insights into clinical strategies.

ShRNA-mediated gene silencing of HDAC11 empowers CAR-T cells against prostate cancer

Epigenetic mechanisms are involved in several cellular functions, and their role in the immune system is of prime importance. Histone deacetylases (HDACs) are an important set of enzymes that regulate and catalyze the deacetylation process. HDACs have been proven beneficial targets for improving the efficacy of immunotherapies. HDAC11 is an enzyme involved in the negative regulation of T cell functions. Here, we investigated the potential of HDAC11 downregulation using RNA interference in CAR-T cells to improve immunotherapeutic outcomes against prostate cancer. We designed and tested four distinct short hairpin RNA (shRNA) sequences targeting HDAC11 to identify the most effective one for subsequent analyses. HDAC11-deficient CAR-T cells (shD-NKG2D-CAR-T) displayed better cytotoxicity than wild-type CAR-T cells against prostate cancer cell lines. This effect was attributed to enhanced activation, degranulation, and cytokine release ability of shD-NKG2D-CAR-T when co-cultured with prostate cancer cell lines. Our findings reveal that HDAC11 interference significantly enhances CAR-T cell proliferation, diminishes exhaustion markers PD-1 and TIM3, and promotes the formation of T central memory TCM populations. Further exploration into the underlying molecular mechanisms reveals increased expression of transcription factor Eomes, providing insight into the regulation of CAR-T cell differentiation. Finally, the shD-NKG2D-CAR-T cells provided efficient tumor control leading to improved survival of tumor-bearing mice in vivo as compared to their wild-type counterparts. The current study highlights the potential of HDAC11 downregulation in improving CAR-T cell therapy. The study will pave the way for further investigations focused on understanding and exploiting epigenetic mechanisms for immunotherapeutic outcomes.

Regulation of mesenchymal stem cell differentiation by autophagy.

Autophagy, a process that isolates intracellular components and fuses them with lysosomes for degradation, plays an important cytoprotective role by eliminating harmful intracellular substances and maintaining cellular homeostasis. Mesenchymal stem cells (MSCs) are multipotent progenitor cells with the capacity for self-renewal that can give rise to a subset of tissues and therefore have potential in regenerative medicine. However, a variety of variables influence the biological activity of MSCs following their proliferation and transplantation in vitro. The regulation of autophagy in MSCs represents a possible mechanism that influences MSC differentiation properties under the right microenvironment, affecting their regenerative and therapeutic potential. However, a deeper understanding of exactly how autophagy is mobilized to function as well as clarifying the mechanisms by which autophagy promotes MSCs differentiation is still needed. Here, we review the current literature on the complex link between MSCs differentiation and autophagy induced by various extracellular or intracellular stimuli and the molecular targets that influence MSCs lineage determination, which may highlight the potential regulation of autophagy on MSCs' therapeutic capacity, and provide a broader perspective on the clinical application of MSCs in the treatment of a wide range of diseases.

A SEPALLATA MADS-Box Transcription Factor, SlMBP21, Functions as a Negative Regulator of Flower Number and Fruit Yields in Tomato.

MADS-box transcription factors act as the crucial regulators in plant organ differentiation. Crop yields are highly influenced by the flower number and fruit growth. However, flower identification is a very complex biological process, which involves many cascade regulations. The molecular mechanisms underlying the genetic regulation of flower identification in cultivated plants, such as tomato, are intricate and require further exploration. In this study, we investigated the vital function of a SEPALLATA (SEP) MADS-box gene, SlMBP21, in tomato sympodial inflorescence meristem (SIM) development for the conversion from SIMs to floral meristems (FMs). SlMBP21 transcripts were primarily accumulated in young inflorescence meristem, flowers, sepals, and abscission zones. The Ailsa Craig (AC++) tomato plants with suppressed SlMBP21 mRNA levels using RNAi exhibited a large increase in flower number and fruit yields in addition to enlarged sepals and inhibited abscission zone development. Scanning electron microscopy (SEM) revealed that the maturation of inflorescence meristems (IMs) was repressed in SlMBP21-RNAi lines. RNA-seq and qRT-PCR analyses showed that numerous genes related to the flower development, plant hormone signal transduction, cell cycle, and cell proliferation et al. were dramatically changed in SlMBP21-RNAi lines. Yeast two-hybrid assay exhibited that SlMBP21 can respectively interact with SlCMB1, SFT, JOINTLESS, and MC, which play key roles in inflorescence meristems or FM development. In summary, our data demonstrate that SlMBP21 functions as a key regulator in SIM development and the conversion from SIMs to FMs, through interacting with other regulatory proteins to control the expression of related genes.

PPA1 promotes adipogenesis by regulating the stability of C/EBPs.

Adipogenesis significantly contributes to healthy adipose tissue expansion in obesity. Increasing adipocyte number or function to alleviate adipose tissue overload could serve as a therapeutic strategy for both lipodystrophy and obesity-related metabolic syndrome. Inorganic pyrophosphatase (PPA1) is an enzyme that catalyzes the hydrolysis of pyrophosphate (PPi) and is involved in many biochemical reactions, but its function in adipose tissue has not been studied previously. In this study, we demonstrated that adipose-specific PPA1 knockout (PPA1AKO) mice showed lipodystrophy and spontaneously developed hepatic steatosis and severe insulin resistance under normal chow diet feeding. PPA1 deficiency suppressed the differentiation of primary adipocyte precursors and 3T3-L1 cells. Notably, PPA1 overexpression can restore inhibited adipogenesis in preadipocytes isolated from db/db mice and type 2 diabetes patients. Mechanistic studies have revealed that PPA1 acts as a positive regulator of early adipocyte differentiation by promoting CCAAT/enhancer-binding proteinβ and δ (C/EBPβ and δ) protein stability. Moreover, the function of PPA1 in adipogenesis is independent of its PPi catalytic activity. Collectively, our in vivo and in vitro findings demonstrated that PPA1 is a novel critical upstream regulator of adipogenesis, controlling adipose tissue development and whole-body metabolic homeostasis.

Downregulation of miR-568 in Atrial Fibrillation Leads to Increased Expression of NAPMT and TRMP7

Aim: Atrial fibrillation (AF) is known as the most common permanent cardiac arrhythmia worldwide with its incidence and prevalence gradually increase with age and cause significant morbidity and mortality. However, the epigenetic alterations underlying the development of this disease remains less understood. MicroRNAs (miRNAs), as one of the epigenetic regulators, are small non-coding RNAs that can target multiple genes to modulate proteins in different signaling pathways. Current studies have demonstrated that miRNAs, which are pivotal regulators of gene expression, may be involved in the pathophysiology of AF. The current study aims to clarify the miRNA regulated cellular signaling in atrial fibrillation. Material and Method: An AF model was generated by providing external electrical stimulation to the HL-1 mouse cardiomyocyte cell line for 24 hours in this study. To understand the molecular mechanisms of miRNAs underlying the AF model, miRNA microarray analysis was performed. The gene sets obtained from the microarray analysis and the bioinformatically obtained putative targets were intersected and pathway enrichment analysis was performed. qRT-PCR was performed for validation of the selected miRNAs and potential targets. Results: miRNA expression profile changes between the control group without external stimulation and the samples at the end of 3-, 6-, 12- and 24-hour stimulation were compared with microarray analysis. In particular, our transcriptomic analysis showed 5 distinctively expressed miRNAs (DEmiRNAs) whose target genes are associated with cardiovascular development within the stimulated groups in HL-1 cells. Additionally, our bioinformatics analysis revealed that targets of these miRNAs are concentrated in biological processes associated with cardiovascular development: smooth muscle cell proliferation, muscle cell proliferation, cell morphogenesis involved in differentiation and regulation of cell differentiation. Specifically, qPCR-based analyses confirmed the inverse correlation of miR-568 and potential targets of this miRNA. While miR-568 expression decreased with prolonged stimulation, expression of its potential targets, NAMPT and TRPM7, increased during prolonged stimulation. Conclusion: This study supported the potential regulative role of miRNAs and their targets in the development of AF.

The Role of the Gap Junction Protein Connexin in Adrenal Gland Tumorigenesis.

Gap junctions (GJs) are important in the regulation of cell growth, morphology, differentiation and migration. However, recently, more attention has been paid to their role in the pathogenesis of different diseases as well as tumorigenesis, invasion and metastases. The expression pattern and possible role of connexins (Cxs), as major GJ proteins, under both physiological and pathological conditions in the adrenal gland, were evaluated in this review. The databases Web of Science, PubMed and Scopus were searched. Studies were evaluated if they provided data regarding the connexin expression pattern in the adrenal gland, despite current knowledge of this topic not being widely investigated. Connexin expression in the adrenal gland differs according to different parts of the gland and depends on ACTH release. Cx43 is the most studied connexin expressed in the adrenal gland cortex. In addition, Cx26, Cx32 and Cx50 were also investigated in the human adrenal gland. Cx50 as the most widespread connexin, along with Cx26, Cx29, Cx32, Cx36 and Cx43, has been expressed in the adrenal medulla with distinct cellular distribution. Considerable effort has recently been directed toward connexins as therapeutically targeted molecules. At present, there exist several viable strategies in the development of potential connexin-based therapeutics. The differential and hormone-dependent distribution of gap junctions within adrenal glands, the relatively large gap junction within this gland and the increase in the gap junction size and number following hormonal treatment would indicate that gap junctions play a pivotal role in cell functioning in the adrenal gland.

TASL mediates keratinocyte differentiation by regulating intracellular calcium levels and lysosomal function

Maintaining epidermal homeostasis relies on a tightly organized process of proliferation and differentiation of keratinocytes. While past studies have primarily focused on calcium regulation in keratinocyte differentiation, recent research has shed light on the crucial role of lysosome dysfunction in this process. TLR adaptor interacting with SLC15A4 on the lysosome (TASL) plays a role in regulating pH within the endo-lysosome. However, the specific role of TASL in keratinocyte differentiation and its potential impact on proliferation remains elusive. In our study, we discovered that TASL deficiency hinders the proliferation and migration of keratinocytes by inducing G1/S cell cycle arrest. Also, TASL deficiency disrupts proper differentiation process in TASL knockout human keratinocyte cell line (HaCaT) by affecting lysosomal function. Additionally, our research into calcium-induced differentiation showed that TASL deficiency affects calcium modulation, which is essential for keratinocyte regulation. These findings unveil a novel role of TASL in the proliferation and differentiation of keratinocytes, providing new insights into the intricate regulatory mechanisms of keratinocyte biology.

The lack of EphB3 receptor prevents bone loss in mouse models of osteoporosis.

Bone homeostasis is a complex process in which some Eph kinase receptors and their ephrin ligands appear to be involved. In the present study we address this issue by examining, both in vitro and in vivo, the role of EphB2 and EphB3 in MSC differentiation into bone tissue. This was firstly evaluated by RT-qPCR and histological staining in MSCs cultured in specific mediums revealing that, whereas EphB2-/- MSCs mainly expressed pro-adipogenic transcription factors, EphB3-/- MSCs showed abundant osteogenic transcripts, such as Runx2, Msx2 and Sp7. To clarify the underlying molecular mechanisms, we found that the lack of EphB3 signaling alters the genetic profile of differentiating MSCs, reducing the expression of many inhibitory molecules and antagonists of the BMP signaling pathway, and increasing Bmp7 expression, a robust bone inductor. Then, to confirm the osteogenic role of EphB3 in vivo, we studied the condition of two mouse models of induced bone loss (ovariectomy or long-term glucocorticoid treatment). Interestingly, in both models, both WT and EphB2-/- mice equally developed the disease but EphB3-/- mice did not exhibit the typical bone loss, nor an increase in urine Ca2+ or blood serum CTX-1. This phenotype in EphB3-KO mice could be due to their significantly higher proportions of osteoprogenitor cells and preosteoblasts, and their lower number of osteoclasts, as compared with WT and EphB2-KO mice. Thus, we conclude that EphB3 acts as a negative regulator of the osteogenic differentiation, and its absence prevents bone loss in mice subjected to ovariectomy or dexamethasone treatment.

The Protective Effects of Taurine, a Non-essential Amino Acid, Against Metals Toxicities: A Review Article.

Taurine is a non-proteinogenic amino acid derived from cysteine. It is involved in several phenomena such as the regulation of growth and differentiation, osmoregulation, neurohormonal modulation, and lipid metabolism. Taurine is important because of its high levels in several tissues such as the central nervous system (CNS), heart, skeletal muscles, retinal membranes, and platelets. In this report, we present the functional properties of taurine indicating that it has potential effects on various metal toxicities. Therefore, a comprehensive literature review was performed using the Scopus, PubMed, and Web of Science databases. According to the search keywords, 61 articles were included in the study. The results indicate that taurine protects tissues against metal toxicity through enhancement of enzymatic and non-enzymatic antioxidant capacity, modulation of oxidative stress, anti-inflammatory and anti-apoptotic effects, involvement in different molecular pathways, and interference with the activity of various enzymes. Taken together, taurine is a natural supplement that presents antitoxic effects against many types of compounds, especially metals, suggesting public consumption of this amino acid as a prophylactic agent against the incidence of metal toxicity.

Loss of PBX1 function in Leydig cells causes testicular dysgenesis and male sterility

Leydig cells are essential components of testicular interstitial tissue and serve as a primary source of androgen in males. A functional deficiency in Leydig cells often causes severe reproductive disorders; however, the transcriptional programs underlying the fate decisions and steroidogenesis of these cells have not been fully defined. In this study, we report that the homeodomain transcription factor PBX1 is a master regulator of Leydig cell differentiation and testosterone production in mice. PBX1 was highly expressed in Leydig cells and peritubular myoid cells in the adult testis. Conditional deletion of Pbx1 in Leydig cells caused spermatogenic defects and complete sterility. Histological examinations revealed that Pbx1 deletion impaired testicular structure and led to disorganization of the seminiferous tubules. Single-cell RNA-seq analysis revealed that loss of Pbx1 function affected the fate decisions of progenitor Leydig cells and altered the transcription of genes associated with testosterone synthesis in the adult testis. Pbx1 directly regulates the transcription of genes that play important roles in steroidogenesis (Prlr, Nr2f2 and Nedd4). Further analysis demonstrated that deletion of Pbx1 leads to a significant decrease in testosterone levels, accompanied by increases in pregnenolone, androstenedione and luteinizing hormone. Collectively, our data revealed that PBX1 is indispensable for maintaining Leydig cell function. These findings provide insights into testicular dysgenesis and the regulation of hormone secretion in Leydig cells.Graphical abstract