Diquat causes mouse testis injury through inducing heme oxygenase-1-mediated ferroptosis in spermatogonia.

Diquat dibromide (DQ) is a globally used herbicide in agriculture, and its overuse poses an important public health issue, including male reproductive toxicity in mammals. However, the effects and molecular mechanisms of DQ on testes are limited. In vivo experiments, mice were intraperitoneally injected with 8 or 10 mg/kg/ day of DQ for 28 days. It has been found that heme oxygenase-1 (HO-1) mediates DQ-induced ferroptosis in mouse spermatogonia, thereby damaging testicular development and spermatogenesis. Histopathologically, we found that DQ exposure caused seminiferous tubule disorders, reduced germ cells, and increased sperm malformation, in mice. Reactive oxygen species (ROS) staining of frozen section and transmission electron microscopy (TEM) displayed DQ promoted ROS generation and mitochondrial morphology alterations in mouse testes, suggesting that DQ treatment induced testicular oxidative stress. Subsequent RNA-sequencing further showed that DQ treatment might trigger ferroptosis pathway, attributed to disturbed glutathione metabolism and iron homeostasis in spermatogonia cells in vitro. Consistently, results of western blotting, measurements of MDA and ferrous iron, and ROS staining confirmed that DQ increased oxidative stress and lipid peroxidation, and accelerated ferrous iron accumulation both in vitro and in vivo. Moreover, inhibition of ferroptosis by deferoxamine (DFO) markedly ameliorated DQ-induced cell death and dysfunction. By RNA-sequencing, we found that the expression of HO-1 was significantly upregulated in DQ-treated spermatogonia, while ZnPP (a specific inhibitor of HO-1) blocked spermatogonia ferroptosis by balancing intracellular iron homeostasis. In mice, administration of the ferroptosis inhibitor ferrostatin-1 effectively restored the increase of HO-1 levels in the spermatogonia, prevented spermatogonia death, and alleviated the spermatogenesis disorders induced by DQ. Overall, these findings suggest that HO-1 mediates DQ-induced spermatogonia ferroptosis in mouse testes, and targeting HO-1 may be an effective protective strategy against male reproductive disorders induced by pesticides in agriculture.

Numerical Simulation and Deformation Prediction of Deep Pit Based on PSO-BP Neural Network Inversion of Soil Parameters.

The finite element numerical simulation results of deep pit deformation are greatly influenced by soil layer parameters, which are crucial in determining the accuracy of deformation prediction results. This study employs the orthogonal experimental design to determine the combinations of various soil layer parameters in deep pits. Displacement values at specific measurement points were calculated using PLAXIS 3D under these varying parameter combinations to generate training samples. The nonlinear mapping ability of the Back Propagation (BP) neural network and Particle Swarm Optimization (PSO) were used for sample global optimization. Combining these with actual onsite measurements, we inversely calculate soil layer parameter values to update the input parameters for PLAXIS 3D. This allows us to conduct dynamic deformation prediction studies throughout the entire excavation process of deep pits. The results indicate that the use of the PSO-BP neural network for inverting soil layer parameters effectively enhances the convergence speed of the BP neural network model and avoids the issue of easily falling into local optimal solutions. The use of PLAXIS 3D to simulate the excavation process of the pit accurately reflects the dynamic changes in the displacement of the retaining structure, and the numerical simulation results show good agreement with the measured values. By updating the model parameters in real-time and calculating the pile displacement under different working conditions, the absolute errors between the measured and simulated values of pile top vertical displacement and pile body maximum horizontal displacement can be effectively reduced. This suggests that inverting soil layer parameters using measured values from working conditions is a feasible method for dynamically predicting the excavation process of the pit. The research results have some reference value for the selection of soil layer parameters in similar areas.

Period circadian regulator 2-mediated steroid hormone synthesis by regulating transcription of steroidogenic acute regulatory protein in porcine granulosa cells.

Steroidogenesis is associated with circadian clock genes. However, the regulation of steroid hormone production in sow granulosal cells by Per2, a crucial circadian regulator, remains unexplored. In this study, we have identified the presence of Per2 in ovarian granulosa cells and have observed its circadian expression pattern. Employing siRNA to interfere with Per2 expression, our investigation revealed that Per2 knockdown notably elevated progesterone (P4) levels along with increasing the expression of StAR but interference of Per2 did not alter the rhythm of clock-related gene (Bmal1, Clock, Per1, and Cry1) in granulosa cells. Subsequent mechanistic analysis showed that Per2 formed complexes with PPARγ and interference with Per2 promoted the formation of the PPARγ:RXRα heterodimer. Importantly, we uncovered that PPARγ:RXRα heterodimer could control the expression of StAR via direct peroxisome proliferator response element binding to its promoter to regulate its activity, and knockdown of Per2 promoted the transcription of StAR via increasing the binding of PPARγ:RXRα ligands. Altogether, these findings indicated a noncanonical role of Per2 in controlling PPARγ:RXRα binding to regulate transcription of StAR and progesterone synthesis, thus revealing potential avenues of pharmacological and therapeutic intervention.

The circadian clock can regulate ovarian function, and disruption of the circadian clock caused by environmental factors can seriously affect the reproductive capacity of female animals, leading to ovarian diseases. Therefore, it is necessary to investigate the relationship between clock genes and ovarian function. In this study, Per2, a key gene for the circadian clock, was expressed in ovarian granulosa cells according to a rhythmic pattern, but knocking out Per2 did not alter the circadian rhythm in granulosa cells. Interference of Per2 notably elevated progesterone (P4) levels along with increasing the expression of StAR (a key gene for P4 synthesis) in granulosa cells. Subsequent mechanistic analysis showed that knockdown of Per2 enhanced transcription of StAR by promoting the formation of the PPARγ:RXRα heterodimer. These results indicated a noncanonical role of Per2 in regulating PPARγ:RXRα binding to control transcription of StAR and P4 production.

Nicotine induces senescence in spermatogonia stem cells by disrupting homeostasis between circadian oscillation and rhythmic mitochondrial dynamics via the SIRT6/Bmal1 pathway.

Infertility is intricately linked with alterations in circadian rhythms along with physiological decline and stem cell senescence. Yet, the direct involvement of circadian mechanisms in nicotine-induced injury to the testes, especially the senescence of spermatogonia stem cells (SSCs), is not well comprehended. This study revealed that nicotine exposure induced testis injury by triggering SSCs senescence along with the upregulation of senescence marker genes and senescence-associated secretory phenotype components. Moreover, nicotine treatment caused mitochondrial hyper-fusion, increased oxidative stress, and DNA damage. Exposure to nicotine was found to suppress the expression of sirtuin 6 (SIRT6), which accelerated the senescence of spermatogonia stem cells (SSCs). This acceleration led to increased acetylation of brain and muscle ARNT-like protein (Bmal1), consequently reducing the expression of Bmal1 protein. Conversely, the overexpression of Bmal1 alleviated mitochondrial hyper-fusion and senescence phenotypes induced by nicotine. Overall, this study unveiled a novel molecular mechanism behind nicotine-induced disorders in spermatogenesis and highlighted the SIRT6/Bmal1 regulatory pathway as a potential therapeutic target for combating nicotine-associated infertility.

Isorhamnetin Improves Oocyte Maturation by Activating the Pi3k/Akt Signaling Pathway.

SCOPE: Isorhamnetin is a natural flavonoid with various pharmacological activities, which can be widely and continuously ingested by humans and animals through their daily diet. The aim of this study is to explore the benefits and molecular mechanisms of isorhamnetin on oocyte maturation. METHODS AND RESULTS: Oocytes are incubated with isorhamnetin (5, 10, 20, and 30 µM) for 44 h. Isorhamnetin (10 µM) increases the polar body extrusion rate of oocytes. Furthermore, isorhamnetin alleviates oxidative stress by inhibiting reactive oxygen species levels and stimulating SOD2 protein expression. The changes in intracellular mitochondrial autophagy and apoptosis-related proteins (Bcl-2, Bax/Bcl-2, and C-Casp3) indicate that isorhamnetin inhibits oocyte apoptosis. Isorhamnetin inhibits endoplasmic reticulum stress by reducing the protein expression of CHOP and GRP78 and improving the normal distribution rate of endoplasmic reticulum. Mechanistic studies show that isorhamnetin activates the PI3K/Akt signaling pathway. CONCLUSION: Isorhamnetin promotes oocyte maturation by inhibiting oxidative stress, mitochondrial dysregulation, apoptosis, and endoplasmic reticulum stress, which have important potential for improving oocyte quality and treating female infertility.