Stem cell technology plays a key role in advancing the understanding of neurological treatments and developing disease models that mimic human conditions. Differentiation of human bone marrow mesenchymal stem cells (hBMSCs) into neurons shows promise for treating neurodegenerative diseases. However, improving the functionality of these nerve cells remains a challenge. Graphene nanoplatelets (GNPs), with their excellent conductivity and biocompatibility, can enhance neuronal differentiation. This study examines the effect of GNPs on hBMSC differentiation. Cells cultured with varying GNP concentrations were assessed at 4 and 7 days using RT-qPCR and immunocytochemistry for neuronal markers MAP2, Nestin, and Tuj1. Results show that GNPs enhance marker expression and promote differentiation. Lower GNP concentrations maintained viability, while higher concentrations were detrimental. Morphological changes and increased fluorescence were observed with a 0.4 µg/ml GNP coating. Calcium imaging with Fluo4-AM indicated increased neuronal activity, underscoring GNPs' role in neuronal maturation. These findings suggest GNPs can drive stem cell differentiation toward neurons, offering new therapeutic potential for neurodegenerative diseases.
Background: Protein acetylation has emerged as essential for sperm function, attracting considerable attention recently. Acetylation, typically mediated by lysine acetyltransferases, involves attaching an acetyl group from acetyl-coenzyme A to lysine residues in proteins. Under alkaline conditions, however, acetylation can occur with minimal enzymatic involvement, primarily due to an elevated pH. As sperm migrate towards the ampulla, they experience increasing intracellular pH (pHi) while undergoing two crucial processes for fertilization: capacitation and the acrosome reaction (AR). Whereas the involvement of acetylating enzymes in these events has been partially investigated, the potential for non-enzymatic acetylation driven by the pHi alkalinization remains unknown.
Results: This study examined protein acetylation (acLys) levels in sperm incubated under capacitating conditions at pH 7.2 and pH 9.0, the latter condition potentially promoting non-enzymatic acetylation. To more precisely investigate the occurrence of non-enzymatic acetylation events, acetyltransferase activity was selectively attenuated using a specific cocktail of inhibitors. The functional implications of these conditions were assessed by examining key fertilization-related sperm attributes, including motility during capacitation and the ability to initiate the AR. Results demonstrated that alkaline conditions elevated basal acLys levels even with reduced acetyltransferase activity (P < 0.05), indicative of non-enzymatic acetylation. α-tubulin, particularly in the midpiece of the sperm flagellum, was identified as a specific target of this modification, correlating with diminished motility during capacitation. Following the AR, acLys levels in the head and midpiece decreased (P < 0.05) under conditions promoting non-enzymatic acetylation, accompanied by reductions in intracellular and acrosomal pH. In contrast, acLys levels and pH in the sperm head incubated under standard capacitating conditions (pH 7.2) remained stable. Sperm exposed to conditions conducive to non-enzymatic acetylation exhibited an impaired ability to trigger the AR (P < 0.05) compared to those maintained at pH 7.2. Notably, diminished acetylase activity emerged as a key factor impairing the maintenance of intracellular and acrosomal pH levels attained during capacitation, even under a pH of 9.0.
Conclusion: This study provides novel evidence for the occurrence of non-enzymatic acetylation in sperm, linked to the modulation of α-tubulin acetylation levels and motility during capacitation. Additionally, it suggests that acetyltransferase activity may play a crucial role in regulating intracellular and acrosomal pH levels in capacitated sperm, facilitating the AR.
Background: Lead is a ubiquitous environmental and industrial pollutant with worldwide health problems. Lead acetate toxicity induces both genotoxic effects and apoptosis. The present study aimed to investigate the usage of mesenchymal stem cells (MSCs) in the treatment of the genotoxic effect of lead acetate (LA) in the testis and its effect on the expression of the apoptosis marker caspase-3 and the proliferation marker Ki-67 in the injured testicular tissue.
Methods: Twenty-one adult male rats were used in this investigation (7 rats/group). Group I received saline and served as the control group (ctrl group); Group II received lead acetate (100 mg/kg) and was called the LA group; Group III received both lead acetate (100 mg/kg) and MSCs (1 × 106 cells/rat) and was called the LA-MSCs group. Body and testis weight, plus semen analysis, were performed in all groups. Reproductive hormones, serotonin, and cortisol were determined in sera. Additionally, oxidative/antioxidative status and lead acetate-induced genetic variations were investigated. Immunohistochemical staining for the proliferation marker Ki-67 and the apoptosis marker caspase-3 was also performed.
Results: revealed that the weight of the body and testis and semen parameters (sperm count, viability, and motility) of the LA group exhibited significant reduction compared to the Ctrl and the LA-MSCs group. In addition, the LA group showed reproductive hormonal imbalance and an increase in oxidative stress biomarkers compared to the LA-MSCs group that showed a significant improvement in these parameters. Compared to the ctrl group, the LA group showed a highly genetic distance value (0.0031), while the LA-MSCs group showed a low genetic distance value (0.0019). This illustrated that the LA-MSCs group exhibited reduced genetic variation induced by LA compared to the LA group. Histological evaluation indicated the presence of severe diffuse degeneration and necrosis in the spermatocytes in the LA group compared to the control one, while co-treatment by MSCs induced significant reduction in these degenerative changes. Immunohistochemical investigation revealed increased expression of the caspase-3 antibody in the testicular tissue of the LA group, while it is significantly decreased in the LA- MSCs group. In contrast, the KI67 antibody revealed a significant decrease in its expression in the LA group, while it was significantly increased in the LA-MSCs group after treatment by MSCs.
Conclusions: It can be concluded that the MSCs are a potential therapeutic for the treatment of testicular dysfunction induced by LA through the reduction of oxidative stress, genotoxic effect, and apoptosis marker caspase-3, and an increase in the proliferation marker Ki-67 in the testicular tissue associated with restoration of hormonal imbalance.
Background: A splice mutation that causes skipping of exon 17 in the KIT gene is a major reason for the dominant white phenotype of pigs. Exon 17 of the KIT gene may be related to differences in testis size and sperm quality among different pig breeds. Investigating the effects of exon 17 of the KIT gene on spermatogonia differentiation and testicular development is essential for understanding the genetic causes of reduced fertility and semen quality in pigs. To better understand the effects of the splice mutation of KIT on porcine spermatogenesis, we described an exon 17 deletion mouse model (Kit D17/+) constructed by simulating splice mutations in KIT for functional verification.
Results: Deletion of exon 17 of Kit severely impaired the differentiation of spermatogonia and promoted the apoptosis of germ cells, resulting in testicular dysplasia and decreased sperm quality and male fertility. Further transcriptomic analysis revealed inhibited expression of genes involved in meiosis and spermatogenesis and attenuated MAPK-ERK signaling in the testicular tissues of Kit D17/+ mice. The attenuated MAPK-ERK signaling caused by impaired Kit phosphorylation was confirmed by western blotting.
Conclusions: Our study demonstrated that deletion of exon 17 of Kit severely impaired spermatogenesis and testicular development, leading to decreased semen quality and male fertility. These findings verified the function of exon 17 in the Kit gene and provide a theoretical basis for improving the semen quality of dominant white pigs through correction of the splice mutation of KIT.
Background: Tau phosphorylation is a tightly regulated process that ensures proper neuronal function. Indeed, hyperphosphorylation of tau closely contributes to neuronal dysfunction leading to neurodegenerative diseases, including tauopathies, which are characterized by excessive and aberrant tau phosphorylation and cognitive decline. Therefore, it is important to understand how to regulate its phosphorylation. In this regard, the protein tyrosine phosphatase receptor delta (PTPRD) has been genetically implicated in tau pathology in humans, but the mechanisms underlying its role in tau regulation remain unclear. This study investigates the impact of Ptprd deficiency on tau phosphorylation, cognitive function, neuroinflammation, and synaptic markers in aging mice.
Results: Mice lacking Ptprd showed increased tau phosphorylation at multiple sites associated with its pathological aggregation. This effect was accompanied by the activation of the tau-related kinase Abl1, particularly in the hippocampus. Behavioral assessments revealed significant impairments in learning and memory, demonstrating the functional impact of these alterations. Moreover, Ptprd knockout mice showed increased microgliosis in both the entorhinal cortex and the hippocampus, suggesting a pro-inflammatory response. Furthermore, the synaptic protein PSD95 was also reduced in the cortex, indicating potential synaptic dysfunction.
Conclusions: The loss of Ptprd leads to increased tau phosphorylation, cognitive impairments, microgliosis, and synaptic alterations in older mice. Our findings also suggest that Ptprd plays a critical role in maintaining tau homeostasis through the Abl1 kinase. This indicates a new potential therapeutic approach for tauopathies, where PTPRD could serve a protective role against tau-related pathologies and may act as a key modulator in disease progression.
Background: The purpose of this work was to examine the fundamental mechanisms of reproductive toxicity in rat models following exposure to Fenpropathrin (FNP). Furthermore, our study explores the novel impacts of Date palm kernel extract (DPK) on these detrimental outcomes.
Methods: Thirty male Wistar rats were used in the investigation. They were split into six groups: one group received corn oil as a control; two groups received DPK at 200 mg/kg and 400 mg/kg; a group received FNP at 4.7 mg/kg; and two combination groups received DPK and FNP at 200 mg/kg and 400 mg/kg, respectively for 60 days.
Results: FNP caused oxidative stress, reduced sperm count, and impaired motility. FNP decreased the expression of the StAR gene and reduced serum testosterone levels. We assessed the histological alterations. In a dose-dependent way, the concurrent administration of DPK extract successfully decreased all the toxicological parameters.
Conclusions: When taken orally, DPK extract may protect against FNP-induced male reproductive toxicity.
Background: Nicotinamide phosphoribosyltransferase (NAMPT) is an enzyme that involves into NMN-NAD + synthesis which involves into cellular metabolism related with aging, immune function, and neurodegeneration. However, its roles in early embryo development are still unclear.
Methods: In present study we disturbed the NAMPT activity and employed immunofluorescence staining and live cell imaging to explore its roles during early embryo development.
Results: We showed that NAMPT mRNA level was stable during mouse early embryo development, and NAMPT accumulated in the nucleus of blastomeres in mouse embryos. The loss of NAMPT activity disturbed the early cleavage from zygote to 2-cell, 4-cell to morula formation in the dose-dependent manner. We found that NAMPT inhibition disrupted mitochondria function in 2-cell embryos, showing decreased mitochondria number and aberrant accumulation in the blastomeres, which further disturb mitochondrial membrane potential level and elevated ROS level in embryos, indicating the occurrence of oxidative stress. Moreover, NAMPT inhibition also increased the apoptotic index, showing with increased Annexin-V signals and apoptotic gene expression.
Conclusions: Taken together, our study provided the evidence that NAMPT was essential for the mitochondria function to control oxidative stress and apoptosis during mouse early embryo development.
Background: Aging affects the reparative potency of mesenchymal stem/stromal cells (MSCs) by diminishing their proliferation and differentiation capability; making them unsuitable for regenerative purposes. Earlier we showed that MSCs acquire the expression of CD45 as a consequence of aging, and this increased expression is associated with downregulated expression of osteogenic markers and upregulated expression of adipogenic and osteoclastogenic markers. However, whether CD45 is actively involved in the aging-mediated deregulated differentiation in the MSCs was not elucidated.
Results: In the present study, we showed that pharmacological inhibition of CD45-specific phosphatase activity in the aged MSCs restores their differentiation potential to young-like. Investigation of the molecular mechanism involved in the process showed that several regulatory kinases like p38, p44/42, Src, and GSK3β are in their dephosphorylated form in the aged MSCs, and importantly, this status gets reversed by the application of a CD45-specific PTP inhibitor. Conversely, pharmacological inhibition of these kinases in young MSCs imposes an aged-like gene expression profile on them. Additionally, we also showed that the secretome of aged MSCs affects the viability and differentiation of primary chondrocytes, and this detrimental effect is reversed by treating aged MSCs with the PTP inhibitor. Our data demonstrate that the aging-mediated expression of CD45 in MSCs alters their differentiation profile by dephosphorylating several kinases and treating the aged MSCs with a CD45 PTP activity inhibitor rejuvenates them.
Conclusions: CD45 can be used as an aging marker for mesenchymal stem cells. Alteration of CD45 phosphatase activity could have significant implications for the use of MSCs in regenerative medicine.
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