In Vitro Cellular & Developmental Biology. Animal最新文献

Effective neovascularization is critical for tissue repair and the enhancement of cardiac function following myocardial infarction (MI). However, the hypoxic microenvironment post-MI significantly impedes neovascular formation. Although ATF4 has been implicated in heart failure and myocardial cell regeneration and repair, its role in angiogenesis remains unclear. This study utilized both in vitro and in vivo models to investigate the role of ATF4 in neovascularization after MI. In hypoxia-cultured murine endothelial cells (ECs), hypoxia was observed to inhibit EC proliferation, migration, and tube formation. In contrast, overexpression of ATF4 ameliorated these hypoxia-induced impairments. Conversely, inhibition of ATF4 further exacerbated the reduction in EC proliferation, migration, and tube formation induced by hypoxia. Notably, the beneficial effects of ATF4 were reversed by the PI3K/AKT inhibitor LY294002. Under hypoxic conditions, ATF4 overexpression significantly upregulated phosphorylated (p)-PI3K, p-AKT (T308), and p-AKT (S473) in ECs. LY294002, however, markedly reduced the expression of p-PI3K, p-AKT (T308), and p-AKT (S473) in hypoxic ECs overexpressing ATF4. In a murine MI model, ATF4 overexpression partially mitigated cardiac dysfunction and promoted neovascularization, effects that were significantly attenuated by LY294002. These findings suggest that ATF4 plays a crucial role in endothelial cell-mediated neovascularization under post-MI hypoxia by modulating the PI3K/AKT signaling pathway.

Recent studies have highlighted the role of ferroptosis in neuronal damage during neonatal hypoxic-ischemic encephalopathy (HIE). Nuclear protein 1 (NUPR1), a newly identified crucial modulator of ferroptosis, remains unexplored in the context of HIE. This study aimed to investigate whether NUPR1 modulates ferroptosis and influences hypoxic-ischemic brain injury through specific molecular mechanisms. NUPR1-knockdown neurons presented increased sensitivity to Erastin-induced neuronal ferroptosis, whereas NUPR1 overexpression conferred resistance. Notably, silencing NUPR1 exacerbated OGD/R-induced neuronal damage and ferroptosis, as evidenced by increased lipid peroxidation, malondialdehyde (MDA) levels, and iron concentrations, as well as decreased glutathione (GSH) levels and altered expression of ferroptosis-related proteins (elevated PTGS2 and reduced GPX4). Conversely, NUPR1 overexpression alleviated OGD/R-induced neuronal damage and ferroptosis. HIE animal model experiments demonstrated that NUPR1 overexpression mitigated brain damage, reduced infarct size, and decreased brain edema, which were correlated with diminished ferroptosis markers. Furthermore, NUPR1 knockdown reduced ferritin heavy chain 1 (FTH1) expression, whereas NUPR1 overexpression increased FTH1 levels, indicating a regulatory role in iron metabolism. Silencing FTH1 reversed the inhibitory effect of NUPR1 on neuronal ferroptosis. Collectively, our findings indicate that NUPR1 protects against ferroptosis in HIE, making it a potential therapeutic target for reducing neuronal injury associated with this condition. NUPR1 suppresses neuronal ferroptosis by increasing FTH1 expression and improving iron storage, enhancing our understanding of the mechanisms involved in ferroptosis in neonatal HIE.

Lipocalin-2 (LCN-2) has a variety of biological functions and produces various effects on adipocytes, such as promoting cell apoptosis, inhibiting preadipocyte differentiation, and weakening insulin signaling. Tumor necrosis factor-α (TNF-α) is one of the first secreted products discovered in adipocytes, which plays an important role in the regulation of adipose metabolism. This experiment was conducted to investigate the regulatory effect of LCN-2 on TNF-α induced inflammatory response in porcine intramuscular adipocytes. Porcine intramuscular adipocytes were cultured in vitro and treated with LCN-2 overexpression or silencing plasmids. After TNF-α treatment, the expressions of LCN-2, interleukin 6 (IL-6), IL-8, and IL-1β were detected by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Western blot analysis was used to detect the expression of phosphatidylinositol 3-kinase (PI3K), total protein kinase B (Akt), and phosphorylated Akt (pAkt) proteins. After the action of the PI3K/Akt pathway inhibitor LY294002, the effects of LCN-2 overexpression on IL-6, IL-8, and IL-1β were evaluated. The results showed that TNF-α induced LCN-2 expression in a dose-/time-dependent manner. Overexpression or silencing of LCN-2 had an impact on TNF-α induced IL-6, IL-8, and IL-1β in porcine intramuscular adipocytes. Overexpression of LCN-2 significantly promoted inflammatory factors IL-6, IL-8, and IL-1β secretion while silencing of LCN-2 inhibited the secretion of these inflammatory factors (P < 0.01). Overexpression of LCN-2 significantly increased the expression of pAkt protein in cells, while silencing of LCN-2 decreased pAkt protein expression (P < 0.01). After blocking the PI3K/Akt signaling pathway, compared with the control group, overexpression of LCN-2 affected IL-6, IL-8, and IL-1β secretion, but the impact was not significant (P > 0.05). This study suggests that LCN-2 regulates TNF-ɑ induced IL-6, IL-8, and IL-1β secretion in porcine intramuscular adipocytes by targeting the PI3K/Akt pathway, which provides a theoretical basis for LCN-2 regulating the inflammatory response of porcine intramuscular adipocytes.

Sperm capacitation, a prerequisite for fertilization, is regulated not only by intrinsic signaling but also by paracrine factors within the female tract. Analysis of previously published RNA-seq datasets identified the ectodysplasin-A2 receptor (EDA2R), an X-linked member of the TNF-receptor superfamily, as a candidate regulator of this process. This study was conducted to test the hypothesis that the EDA-A2/EDA2R axis is a regulator that directly regulates sperm capacitation during fertilization process. Western blotting and immunofluorescence showed that EDA2R was localized in late spermatogenic cells and in the midpiece of epididymal sperm. Incubation of mouse sperm in HTF medium containing the corresponding ligand EDA-A2 (0-1 µg/mL) resulted in a dose-dependent improvement in the amplitude of lateral head displacement and curvilinear velocities. Ligand exposure promoted the appearance of capacitation hallmarks: tyrosine phosphorylation level was elevated within 30 min and the proportion of FITC-PNA positive, acrosome-reacted cells increased at 30 and 60 min (p < 0.05). The EDA-A2 treated sperm yielded a higher cleavage rate (78.5% vs. 48.3%) and a higher blastocyst formation rate (97.6% vs. 88.4%) after in vitro fertilization. qPCR in hormonally synchronized females revealed transient ovarian and prolonged oviductal Eda-a2 upregulation surrounding ovulation, suggesting that the ligand is present at the site of sperm-oocytes fertilization. These results clarify that EDA-A2/EDA2R is a rapid physiological driver of sperm capacitation. This provides a tractable cytokine axis for optimizing assisted reproduction.

Studies in rodents have shown that systemic inflammation induced by prenatal exposure to the viral mimetic polyinosinic:polycytidylic acid (Poly I:C) triggers maternal immune activation. Cytokines released by the maternal immune system can cross the placenta and enter fetal circulation. In the fetal brain, embryonic microglia may produce additional cytokines and other inflammatory mediators in response to maternally derived cytokines. This resulting cytokine imbalance is suggested to impair neurogenesis and brain development, potentially contributing to the onset of neuropsychiatric disorders in offspring. To investigate microglial involvement in neurogenesis under pathological conditions, we used the spontaneously immortalized microglial cell line (SIM-A9), and confirmed the expression of Iba1 and CD68 via immunocytochemistry. Additionally, SIM-A9 cells expressed CX3CR1, Ki67, and isolectin. Upon Poly I:C stimulation, SIM-A9 cells released the cytokines interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), as well as nitric oxide (NO), as determined by ELISA and Griess assay, respectively. After confirming SIM-A9 cell activation by Poly I:C, we co-cultured these cells with neural stem/progenitor cells (NSPCs) from embryonic mouse neocortex using a transwell system. We examined how chronically activated microglia influence NSPC differentiation and characterized the resulting cell phenotypes using immunocytochemistry. Our results demonstrate that SIM-A9 cells support NSPC differentiation into neurons as early as three days in culture. However, the number of neurons decreased with prolonged culture. Furthermore, Poly I:C in the NSPC culture media, as well as cytokines secreted by Poly I:C-activated SIM-A9 cells, showed a supportive effect on astrocyte differentiation.