Microcystin-LR accelerates follicular atresia in mice via JNK-mediated adherent junction damage of ovarian granulosa cells

The cytotoxicity of microcystin-LR: ultrastructural and functional damage of cells

Microcystin-LR (MC-LR) is a toxin produced by cyanobacteria, which is widely distributed in eutrophic water bodies and has multi-organ toxicity. Previous cytotoxicity studies have mostly elucidated the effects of MC-LR on intracellular-related factors, proteins, and DNA at the molecular level. However, there have been few studies on the adverse effects of MC-LR on cell ultrastructure and function. Therefore, research on the cytotoxicity of MC-LR in recent years was collected and summarized. It was found that MC-LR can induce a series of cytotoxic effects, including decreased cell viability, induced autophagy, apoptosis and necrosis, altered cell cycle, altered cell morphology, abnormal cell migration and invasion as well as leading to genetic damage. The above cytotoxic effects were related to the damage of various ultrastructure and functions such as cell membranes and mitochondria. Furthermore, MC-LR can disrupt cell ultrastructure and function by inducing oxidative stress and inhibiting protein phosphatase activity. In addition, the combined toxic effects of MC-LR and other environmental pollutants were investigated. This review explored the toxic targets of MC-LR at the subcellular level, which will provide new ideas for the prevention and treatment of multi-organ toxicity caused by MC-LR.

Differentially expressed transcripts study during pregnancy and postpartum anestrus of yak (Bos grunniens)

Background: Yak is the main livestock species in the plateau area, and its reproductive performance is low, usually two years or three years. A very few of yaks recover within a certain period of time after delivery and smoothly enter the next estrous cycle, while most of them enter the postpartum anestrus and show no estrus performance. However, the key biological factors and influencing mechanisms that cause postpartum anestrus in yaks are not clear. Objective: To study the expression of differential transcripts in ovaries of yak during pregnancy and postpartum anestrus. Methods: Each three yaks in pregnancy and anestrus under natural grazing conditions in Haiyan County, Qinghai Province were selected and slaughtered, and their ovaries were collected and sent to Biomarker Technologies. Oxford Nanopore Technologies single-molecule real-time electrical signal sequencing technology was used to perform full-length transcriptome sequencing. Astalavista software was used to identify the types of alternative splicing events in yak estrus and pregnancy, and TAPIS pipeline was used to identify alternative polyadenylation. Results: The results showed that there were 1751 differentially expressed transcripts (DETs) between pregnancy and anestrus in yak, of which 808 were upregulated and 943 were downregulated. GO analysis showed that the biological processes of DETs were mainly reproductive, reproductive and rhythmic processes. KEGG analysis showed that the DET cell junction-related adhesion junction protein (β-catenin) and amino terminal kinase (JNK) were involved in FAs (local adhesion). Phosphatidylinositol-3-kinase (PI3K) is involved in the PI3K/AKT/mTOR signaling pathway. Circadian rhythm output cycle failure (Clock) and brain and muscle tissue aromatic hydrocarbon receptor nuclear transporter-like protein 1 (Bmal1) are involved in circadian rhythm signaling pathway. Conclusion: This study found that β-catenin, JNK, PI3K, Clock and Bmal1 were closely related to postpartum anestrus in yak.

Multigenerational genetic effects of paternal cadmium exposure on ovarian granulosa cell apoptosis

To explore whether paternal cadmium (Cd) exposure causes ovarian granulosa cell (GC) apoptosis in offspring and the multigenerational genetic effects. From postnatal day 28 (PND28) until adulthood (PND56), SPF male Sprague-Dawley (SD) rats were gavaged daily with varying concentrations of CdCl_2. (0, 0.5, 2, and 8 mg/kg). After treatment, the F1 generation was produced by mating with untreated female rats, and the F1 generation male rats were mated with untreated female rats to produce the F2 generation. Apoptotic bodies (electron microscopy) and significantly higher apoptotic rates (flow cytometry) were observed in both F1 and F2 ovarian GCs following paternal Cd exposure. Moreover, the mRNA (qRTPCR) or protein (Western blotting) levels of bax, bcl2, bcl-xl, caspase 3, caspase 8, and caspase 9 were changed to varying degrees. Apoptosis-related miRNAs (qRTPCR) and methylation modifications of apoptosis-related genes (bisulfite-sequencing PCR) in ovarian GCs were further detected. Compared with those of controls, the expression patterns of miRNAs in F1 and F2 offspring were different after paternal Cd exposure, while the average methylation level of apoptosis-related genes did not change significantly (except for individual loci). In summary, there are paternal genetic intergenerational and transgenerational effects on ovarian GC apoptosis induced by paternal Cd exposure. These genetic effects were related to the upregulation of BAX, BCL-XL, Cle-CASPASE 3, and Cle-CASPASE 9 in F1 and the upregulation of Cle-CASPASE 3 in F2 progeny. Important changes in apoptosis-related miRNAs were also observed.

Microcystin leucine arginine induces human sperm damage: Involvement of the Ca2+/CaMKKβ/AMPK pathway

As a common pollutant in the water environment, microcystin leucine arginine (MC-LR) can enter semen and damage the sperm in animals. However, the mechanism by which MC-LR damages human sperm is unclear. Therefore, human sperm samples were obtained from the Henan Provincial Sperm Bank and exposed to different concentrations (0, 1, 10, and 100 μg/L) of MC-LR for 1, 2, 4, and 6 h, to invegest the effects and potential mechanism of MC-LR on sperm. The results showed that MC-LR mainly accumulated in the neck and flagellum of human sperm. Compared to the control group, the sperm capacitation rate and motility were significantly decreased in the 100 μg/L group. After exposure of 100 μg/L of MC-LR, the central microtubule and microtubule doublet of sperm flagellum were blurred, asymmetrical, or even lost. Furthermore, the expression levels of flagellin DNAH17, SPEF2, SPAG16, SPAG6, and CFAP44 in human sperm were reduced. Also, the phosphorylation levels of CaMKKβ and AMPK can be inhibited by MC-LR. These findings revealed that MC-LR can induce functional and structural damage in human sperm, and the Ca²⁺/CaMKKβ/AMPK pathway may be involved in this process. This study will provide a basis for prevention and treatment of male fertility declines caused by MC-LR.