Protegrin-1 inhibits porcine ovarian granulosa cell apoptosis from H2O2-induced oxidative stress via the PERK/eIF2α/CHOP signaling pathway in vitro

CXCR2, as a key regulatory gene of HDP-PG-1, maintains intestinal mucosal homeostasis

The intestine defends against pathogenic microbial invasion via the secretion of host defense peptides (HDPs). Nutritional immunomodulation can stimulate the expression of endogenous HDPs and enhance the body's immune defense, representing a novel non-antibiotic strategy for disease prevention. The project aims to explore the regulatory mechanism of protegrin-1 (PG-1) expression using sodium phenylbutyrate (PBA) by omics sequencing technology and further investigate the role of key regulatory genes on intestinal health. The results showed that PBA promoted PG-1 expression in intestinal epithelial cells based on cell density through epidermal growth factor receptor (EGFR) and G protein-coupled receptor (GPR43). Transcriptome sequencing and microRNA sequencing revealed that C-X-C motif chemokine receptor 2 (CXCR2) exhibited interactions with PG-1. Pre-treatment cells with a CXCR2 inhibitor (SB225002) effectively suppressed the induction of PG-1 by PBA. Furthermore, SB225002 significantly suppressed the gene expression of HDPs in the jejunum of mice without influencing on the morphology, number of goblet cells, and proliferation of the intestine. CXCR2 inhibition significantly reduced the expression of HDPs during E. coli infection, and resulted in the edema of jejunal epithelial cells. The 16S rDNA analysis of cecal contents showed that the E. coli and SB225002 treatments changed gut microbiota diversity and composition at different taxonomic levels. Correlation analysis suggested a potential regulatory relationship between gut microbiota and HDPs. To that end, a gene involved in the HDP expression, CXCR2, has been identified in the study, which contributes to improving intestinal immune function. PBA may be used as a functional additive to regulate intestinal mucosal function, thereby enhancing the health of the intestinal and host.

Ovarian PERK/NRF2/CX43/StAR/progesterone pathway activation mediates female reproductive dysfunction induced by cold exposure

Ambient air temperature is a key factor affecting human health. Female reproductive disorders are representative health risk events under low temperature. However, the mechanism involving in cold-induced female reproductive disorders remains largely unknown. Female mice were intermittently exposed to cold conditions (4 °C) to address the health risk of low temperature on female reproductive system. Primary granulosa cells (GCs) were prepared and cultured under low temperature (35 °C) or exposed to β3-adrenoreceptor agonist, isoproterenol, to mimic the condition of cold exposure. Western-blot, RT-PCR, co-IP, ELISA, pharmacological inhibition or siRNA-mediated knockdown of target gene were performed to investigate the possible role of hormones, gap conjunction proteins, and ER stress sensor protein in regulating female reproductive disorders under cold exposure. Cold exposure induced estrous cycle disorder and follicular dysplasia in female mice, accompanying with abnormal upregulation of progesterone and its synthetic rate-limiting enzyme, StAR, in the ovarian granulosa cells. Under the same conditions, an increase in connexin 43 (CX43) expressions in the GCs was also observed, which contributed to elevated progesterone levels in the ovary. Moreover, ER stress sensor protein, PERK, was activated in the ovarian GCs after cold exposure, leading to the upregulation of downstream NRF2-dependent CX43 transcription and aberrant increase in progesterone synthesis. Most importantly, blocking PERK expression in vivo significantly inhibited NRF2/CX43/StAR/progesterone pathway activation in the ovary and efficiently rescued the prolongation of estrous cycle and the increase in follicular atresia of the female mice induced by cold stress. We have elucidated the mechanism of ovarian PERK/NRF2/CX43/StAR/progesterone pathway activation in mediating female reproductive disorder under cold exposure. Targeting PERK might be helpful for maintaining female reproductive health under cold conditions.

Transcriptome profiling reveals transcriptional regulation of Protegrin-1 on immune defense and development in porcine granulosa cells

Protegrin-1 (PG1) is an antimicrobial peptide (AMP) that has garnered increasing attention due to its potent immune defense activity. Our previous studies demonstrated the ability of PG1 to enhance proliferation and inhibit apoptosis of porcine granulosa cells (GCs) under oxidative stress. GCs play a crucial role in ovary follicular development. However, the specific function and underlying mechanisms of AMP in follicular development still need further elucidation. The present study aimed to comprehensively explore the biological effects of PG1 on porcine GCs using transcriptome profiling by RNA sequencing technology. Isolated GCs were incubated with or without PG1 for 24 h and transcriptome-wide analysis was exerted to identify differentially expressed genes (DEGs). The results of expression analysis revealed 1,235 DEGs, including 242 up-regulated genes and 993 down-regulated genes (|log2 (FoldChange)| > 1; adjusted P-value < 0.05). The expression levels of 7 selected DEGs were validated by quantitative reverse transcription-polymerase chain reaction (RT-qPCR) analysis, which was consistent with the RNA-sequencing data. Among the significant DEGs, several genes associated with GC function and ovarian follicle development were identified, such as estrogen receptor 2 (ESR2), growth and differentiation factor 6 (GDF6), cell division cycle 20 homolog (CDC20), Notch3, ephrin and Eph receptor system, Egl nine homolog 3 (EGLN3), and BCL2 like 14 (BCL2L14). Gene Ontology (GO) analysis revealed that the top three significant GO terms were inflammatory response, defense response, and granulocyte migration. Additionally, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis presented that DEGs were mainly enriched in the immune system, infectious disease, signaling molecules and interaction, and immune disease. Furthermore, Ingenuity Pathway Analysis (IPA) predicted that the top activated pathway was Liver X Receptor (LXR)/ Retinoid X Receptor (RXR) Activation which is known to be associated with female reproduction. Predicted protein-protein interactions (PPIs) analysis identified complement C3 (C3) as the top node with the highest degree of network connection and revealed that DEGs in the sub-networks were involved in cytokine-cytokine receptor interaction, neuroactive ligand-receptor interaction, chemokine signaling pathway, and metabolic process. In conclusion, this study expanded the understanding of the effects of PG1 on porcine GCs at the transcriptomic level and provided a theoretical basis for further investigation into the role of PG1 in immune defense and mammalian ovarian follicular development.

Cypermethrin and/or sulfamethoxazole exposure effect on apoptosis and endoplasmic reticulum of grass carp cardiomyocyte

With the soar use range of pesticides and antibiotics in agricultural production, the pollution of surrounding runoff has become more severe; thus, the health and safety of non-target species such as fish are at risk. Excessive amounts of cypermethrin (CMN, 0.651 mg/l) and sulfamethoxazole (SMZ, 0.3 mg/l) are known to trigger oxidative stress and endoplasmic reticulum stress, resulting in toxic effects on cells. The damage degree of poisons on grass carp and the effect of the corresponding axis pathway PERK/eif2α/CHOP are still unknown. Therefore, our study set up two single poison groups (CMN/SMZ) and a combined poison group (CMN&SMZ) to detect this pathway and related indicators. After detection, the content of MDA both in CMN and SMZ group myocardium tissue was increased, while the SOD, CAT activity and GSH levels were decreased. Apoptosis-related genes (Bax, PUMA, P53 and Caspase-3/9), inflammation-related genes (TNF-α, iNOS and IL-1β/6/8), ER stress pathway PERK/eif2α/CHOP and related genes (ATF6, IRE1a and GRP78) were all increased; in contrast, the anti-apoptotic gene Bcl-2 was down-regulated. From the overall trend observation, the apoptosis proportion of cardiomyocytes in the combined poison group was higher than that of the single poison. In summary, this study shows that CMZ and SMZ can induce oxidative stress and subsequent ER stress in grass carp cardiomyocytes by regulating the PERK/eif2α/CHOP signaling axle, thereby inducing apoptosis, and followed by inflammatory responses. The combined effect of the CMZ and SMZ mixture was severer than that of a single poison (CMZ or SMZ), so it can be inferred that the damage degree of grass carp myocardium tissue would be aggravated with the appearance of CMZ or/and SMZ. The experimental results of this study have suggestions and warnings for the toxicological research of CMZ and SMZ and the management of industrial and ecological balance.

Sirtuin 3 regulation: a target to alleviate β-hydroxybutyric acid-induced mitochondrial dysfunction in bovine granulosa cells

BACKGROUND

During the transition period, the insufficient dry matter intake and a sharply increased in energy consumption to produce large quantities of milk, high yielding cows would enter a negative energy balance (NEB) that causes an increase in ketone bodies (KBs) and decrease in reproduction efficiency. The excess concentrations of circulating KBs, represented by β-hydroxybutyric acid (BHBA), could lead to oxidative damage, which potentially cause injury to follicular granulosa cells (fGCs) and delayed follicular development. Sirtuin 3 (Sirt3) regulates mitochondria reactive oxygen species (mitoROS) homeostasis in a beneficial manner; however, the molecular mechanisms underlying its involvement in the BHBA-induced injury of fGCs is poorly understood. The aim of this study was to explore the protection effects and underlying mechanisms of Sirt3 against BHBA overload-induced damage of fGCs.

RESULTS

Our findings demonstrated that 2.4 mmol/L of BHBA stress increased the levels of mitoROS in bovine fGCs. Further investigations identified the subsequent mitochondrial dysfunction, including an increased abnormal rate of mitochondrial architecture, mitochondrial permeability transition pore (MPTP) opening, reductions in mitochondrial membrane potential (MMP) and Ca²⁺ release; these dysfunctions then triggered the caspase cascade reaction of apoptosis in fGCs. Notably, the overexpression of Sirt3 prior to treatment enhanced mitochondrial autophagy by increasing the expression levels of Beclin-1, thus preventing BHBA-induced mitochondrial oxidative stress and mitochondrial dysfunction in fGCs. Furthermore, our data suggested that the AMPK-mTOR-Beclin-1 pathway may be involved in the protective mechanism of Sirt3 against cellular injury triggered by BHBA stimulation.

CONCLUSIONS

These findings indicate that Sirt3 protects fGCs from BHBA-triggered injury by enhancing autophagy, attenuating oxidative stress and mitochondrial damage. This study provides new strategies to mitigate the fGCs injury caused by excessive BHBA stress in dairy cows with ketosis.

Kurarinone attenuates hydrogen peroxide-induced oxidative stress and apoptosis through activating the PI3K/Akt signaling by upregulating IGF1 expression in human ovarian granulosa cells

Dysregulated follicular development may lead to follicular atresia, and this is associated with oxidative stress in granulosa cells. Kurarinone is a natural compound possessing multiple activities, including antioxidative ability. However, the role of kurarinone in granulosa cell damage during follicular atresia remains unknown. Human ovarian granulosa KGN cells were treated with hydrogen peroxide (H₂ O₂ ) to induce cellular damage. Cytotoxicity was investigated by lactate dehydrogenase (LDH) release assay. Oxidative stress was evaluated by detection of reactive oxygen species (ROS) generation and oxidative biomarker levels. Cell apoptosis was evaluated by flow cytometry, a Cell Death Detection ELISA Kit, and a Caspase-3 Assay Kit. The downstream target and related signaling pathway were analyzed by western blotting. Kurarinone attenuated H₂ O₂ -induced LDH release in KGN cells. Kurarinone relieved H₂ O₂ -induced increase in ROS generation and malondialdehyde level as well as decrease in superoxide dismutase-1 activity and heme oxygenase 1 and NAD(P)H quinone dehydrogenase 1 mRNA levels. Kurarinone inhibited H₂ O₂ -induced apoptosis in KGN cells. Kurarinone targeted insulin-like growth factor 1 (IGF1) and upregulated IGF1 expression to activate the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling. IGF1 silencing attenuated the suppressive effects of kurarinone on H₂ O₂ -induced oxidative stress and apoptosis in KGN cells. In conclusion, kurarinone attenuates H₂ O₂ -induced oxidative stress and apoptosis in KGN cells through activating the PI3K/Akt signaling by upregulating IGF1 expression, indicating the therapeutic potential of kurarinone in follicular atresia.

A Mutation in Endogenous saRNA miR-23a Influences Granulosa Cells Response to Oxidative Stress

Phenotypes are the result of the interaction between the gene and the environment, so the response of individuals with different genotypes to an environment is variable. Here, we reported that a mutation in miR-23a influences granulosa cells (GCs) response to oxidative stress, a common mechanism of environmental factors affecting female reproduction. We showed that nuclear miR-23a is a pro-apoptotic miRNA in porcine GCs through the activation of the transcription and function of NORHA, a long non-coding RNA (lncRNA) induces GC apoptosis and responses to oxidative stress. Mechanistically, miR-23a acts as an endogenous small activating RNA (saRNA) to alter histone modifications of the NORHA promoter through the direct binding to its core promoter. A C > T mutation was identified at −398 nt of the miR-23a core promoter, which created a novel binding site for the transcription factor SMAD4 and recruited the transcription repressor SMAD4 to inhibit miR-23a transcription and function in GCs. Notably, g.−398C > T mutation in the miR-23a promoter reduced GCs response to oxidative stress. In addition, g.−398C > T mutation was significantly associated with sow fertility traits. In short, our findings preliminarily revealed the genetic basis of individual differences in the response to oxidative stress from the perspective of a single mutation and identified miR-23a as a candidate gene for the environmental adaptation to oxidative stress.