RESUMO
A recent study has introduced a recombinant fusion protein, consisting of the extracellular domain (ECD) of p75 and the Fc fragment of human immunoglobulin IgG1 (p75ECD-Fc), as a multifaceted agent within the nervous system. This research aimed to assess the effects of p75ECD-Fc on neuronal growth and the restoration of neurological functions in rats afflicted with neonatal hypoxic-ischemic encephalopathy (NHIE). In vitro analyses revealed that 1⯵M p75ECD-Fc treatment markedly increased cell viability and facilitated neurite outgrowth in neurons exposed to oxygen-glucose deprivation (OGD). Subsequent in vivo studies determined that a dose of 78.6⯵g/3⯵l of p75ECD-Fc significantly mitigated brain damage and both acute and long-term neurological impairments, outperforming the therapeutic efficacy of hypothermia, as evidenced through behavioral assessments. Additionally, in vivo immunostaining showed that p75ECD-Fc administration enhanced neuronal survival and regeneration, and reduced astrocytosis and microglia activation in the cortex and hippocampus of NHIE rats. A noteworthy shift from A1 to A2 astrocyte phenotypes and from M1 to M2 microglia phenotypes was observed after p75ECD-Fc treatment. Furthermore, a co-expression of the p75 neurotrophin receptor (p75NTR) and Nestin was identified, with an overexpression of Nestin alleviating the neurological dysfunction induced by NHIE. Mechanistically, the neuroprotective effects of p75ECD-Fc, particularly its inhibition of neuronal apoptosis post-OGD, may be attributed to Nestin. Taken together, these results highlight the neuroprotective and anti-inflammatory effects of p75ECD-Fc treatment through the modulation of glial cell phenotypes and the Nestin-mediated inhibition of neuronal apoptosis, positioning it as a viable therapeutic approach for NHIE.
RESUMO
Background: Infertility is a global medical and social problem that affects human health and social development. At present, about 15% of couples of the right age in the world are infertile. As all we know, genetic defects are the most likely underlying cause of the pathology. ATP5D is also known as the delta subunit of mitochondrial ATP synthase. Mitochondria maintain sperm vitality, capacitation, acrosome reaction, and DNA integrity through ATP. Mitochondrial damage can trigger energy synthesis disorders, resulting in decreased sperm quality and function or even disappearance. The specific role of ATP5D in regulation of the male reproductive system remains elusive. Methods: In this study, semen from normal and infertile males were collected and their indicators were examined by analysis of routine sperm parameters; ATP5D protein content in semen was examined by ELISA. Singer sequencing was used to detect whether there was a mutated of ATP5D in semen. Meanwhile, ATP5D knockout (KO) and knockin (KI) male mice were selected at 8-12 weeks of age and mated with adult wild-type (WT) female mice for more than two months to assess their fertility and reproductive ability. Morphological changes in tissues such as testes and epididymis were observed by HE staining; spermatozoa were taken from the epididymis of the mice; sperm counts were performed and morphological changes were observed by Diff-Quik staining. Results: The results showed that the expression of ATP5D in infertile males was significantly lower than that in normal males (P < 0.001) and the normal morphology rate of spermatozoa was much lower than that of normal males, and the sequencing results showed no mutations. The animal reproductive experiments showed no significant changes in the number of fertility in KO/KI mice compared with WT mice, but the duration of fertility was significantly longer (P = 0.02). The testicular cells in KO mice were loosely arranged and disorganized, the lumen was larger, the interstitial cells were atrophied, and the number of spermatozoa was reduced and the malformation rate was higher in WT males. This suggests that ATP5D is an essential protein for sperm formation and fertility in male mice and may be used as a biomarker of male fertility. Conclusion: This study found ATP5D correlated with male infertility and the expression levels were significantly reduced in the seminal plasma of all male infertile patients without gene mutations. KO male significantly prolonged fertility time and impaired testicular histomorphology. This suggests that ATP5D may be associated with spermatogenic function and fertility in male mice and may be used as a biomarker for male fertility. Future studies are required to elucidate the potential mechanisms. The trial registration number is KLL-2021-266.