Effect of 43 degrees treatment on expression of heat shock proteins 105, 70 and 60 in cultured monkey Sertoli cells

Calycosin Enhances Heat Shock Related-Proteins in H9c2 Cells to Modulate Survival and Apoptosis against Heat Shock

Heat shock proteins (HSPs), which function as chaperones, are activated in response to various environmental stressors. In addition to their role in diverse aspects of protein production, HSPs protect against harmful protein-related stressors. Calycosin exhibits numerous beneficial properties. This study aims to explore the protective effects of calycosin in the heart under heat shock and determine its underlying mechanism. H9c2 cells, western blot, TUNEL staining, flow cytometry, and immunofluorescence staining were used. The time-dependent effects of heat shock analyzed using western blot revealed increased HSP expression for up to 2[Formula: see text]h, followed by protein degradation after 4[Formula: see text]h. Hence, a heat shock damage duration of 4[Formula: see text]h was chosen for subsequent investigations. Calycosin administered post-heat shock demonstrated dose-dependent recovery of cell viability. Under heat shock conditions, calycosin prevented the apoptosis of H9c2 cells by upregulating HSPs, suppressing p-JNK, enhancing Bcl-2 activation, and inhibiting cleaved caspase 3. Calycosin also inhibited Fas/FasL expression and activated cell survival markers (p-PI3K, p-ERK, p-Akt), indicating their cytoprotective properties through PI3K/Akt activation and JNK inhibition. TUNEL staining and flow cytometry confirmed that calycosin reduced apoptosis. Moreover, calycosin reversed the inhibitory effects of quercetin on HSF1 and Hsp70 expression, illustrating its role in enhancing Hsp70 expression through HSF1 activation during heat shock. Immunofluorescence staining demonstrated HSF1 translocation to the nucleus following calycosin treatment, emphasizing its cytoprotective effects. In conclusion, calycosin exhibits pronounced protective effects against heat shock-induced damages by modulating HSP expression and regulating key signaling pathways to promote cell survival in H9c2 cells.

Mechanism of mitochondrial oxidative phosphorylation disorder in male infertility

ABSTRACT

Male infertility has become a global concern, accounting for 20-70% of infertility. Dysfunctional spermatogenesis is the most common cause of male infertility; thus, treating abnormal spermatogenesis may improve male infertility and has attracted the attention of the medical community. Mitochondria are essential organelles that maintain cell homeostasis and normal physiological functions in various ways, such as mitochondrial oxidative phosphorylation (OXPHOS). Mitochondrial OXPHOS transmits electrons through the respiratory chain, synthesizes adenosine triphosphate (ATP), and produces reactive oxygen species (ROS). These mechanisms are vital for spermatogenesis, especially to maintain the normal function of testicular Sertoli cells and germ cells. The disruption of mitochondrial OXPHOS caused by external factors can result in inadequate cellular energy supply, oxidative stress, apoptosis, or ferroptosis, all inhibiting spermatogenesis and damaging the male reproductive system, leading to male infertility. This article summarizes the latest pathological mechanism of mitochondrial OXPHOS disorder in testicular Sertoli cells and germ cells, which disrupts spermatogenesis and results in male infertility. In addition, we also briefly outline the current treatment of spermatogenic malfunction caused by mitochondrial OXPHOS disorders. However, relevant treatments have not been fully elucidated. Therefore, targeting mitochondrial OXPHOS disorders in Sertoli cells and germ cells is a research direction worthy of attention. We believe this review will provide new and more accurate ideas for treating male infertility.

Acute heat stress reduces viability but increases lactate secretion of porcine immature Sertoli cells through transcriptome reprogramming

Sertoli cells, important constituents of the somatic niche, supports the growth and development of spermatogonia. Heat stress (HS), among multiple intrinsic and external factors, can induce physiological and biochemical changes in Sertoli cells. However, the underlying molecular mechanism remains largely unclear. Here, we showed that acute heat stress (43 °C, 0.5 h) could reduce cell viability, promote apoptosis, and increase the lactate production of porcine immature Sertoli cells (iSCs) cultured in vitro. Then, transcriptome sequencing identified 126 immediately and 3372 prolonged responded differentially expressed genes (DEGs) after acute heat stress (43 °C, 0.5 h) (HS0.5), and 36 h recovery culture following heat stress (HS0.5-R36), respectively. Enrichment analyses found different signaling pathways: immediate changes including cell response to heat, regulation of cellular response to stress, heat shock protein binding, chaperon-mediated protein folding, and sterol biosynthetic process, but prolonged changes mainly involving cell cycle, regulation of apoptotic process/cell proliferation, reproductive process, P53, PI3K-Akt and Glycolysis/Gluconeogenesis. Furthermore, transcriptional patterns of 9 DEGs (Dnajb1, Traf6, Insig1, Gadd45g, Hdac6, Fkbp4, Serpine1, Pfkp and Galm), and 6 heat shock proteins (HSPs) (Hspa6, Hspb1, Hspd1, HSP90aa1, HSP90ab1 and Hsph1) were validated, as well as the protein pattern of HSP90AA1 via immunostaining and western blot. Taken together, heat stress could initiate immediate changes of heat shock-related genes, and reprogram transcriptome and signaling pathways affecting the viability, apoptosis and metabolite production of pig iSCs.

Cold-induced RNA-binding protein (CIRBP) regulates the expression of Src-associated during mitosis of 68 kDa (Sam68) and extracellular signal-regulated kinases (ERK) during heat stress-induced testicular injury

In this study, the ability of cold-induced RNA-binding protein (CIRBP) to regulate the expression of Src-associated during mitosis of 68 kDa (Sam68) and extracellular signal-regulated kinases (ERK) in the mouse testis and mouse primary spermatocytes (GC-2spd cell line) before and after heat stress was examined to explore the molecular mechanism by which CIRBP decreases testicular injury. A mouse testicular hyperthermia model, a mouse primary spermatocyte hyperthermia model and a low CIRBP gene-expression cell model were constructed and their relevant parameters were analysed. The mRNA and protein levels of CIRBP and Sam68 were significantly decreased in the 3-h and 12-h testicular heat-stress groups, extracellular signal-regulated kinase 1/2 (ERK1/2) protein expression was not significantly affected but phospho-ERK1/2 protein levels were significantly decreased. GC-2spd cellular heat-stress results showed that the mRNA and protein concentrations of CIRBP and Sam68 were reduced 48h after heat stress. In the low CIRBP gene-expression cell model, CIRBP protein expression was significantly decreased. Sam68 mRNA expression was significantly decreased only at the maximum transfection concentration of 50nM and Sam68 protein expression was not significantly affected. These findings suggest that CIRBP may regulate the expression of Sam68 at the transcriptional level and the expression of phospho-ERK1/2 protein, both of which protect against heat-stress-induced testicular injury in mice.

Effects of elevated ambient temperature and local testicular heating on the expressions of heat shock protein 70 and androgen receptor in boar testes

Heat stress damaged spermatogenesis and semen quality, however, the exact molecular mechanism is not clear. The objective of this study was to determine the effects of elevated ambient temperature and local testicular heating on the expressions of heat shock protein 70 and androgen receptor in boar testes. A growing body of evidence demonstrated that germ cell apoptosis can be aggravated by heat stress and androgen deprivation, and at normal temperature, withdrawal of androgen led to germ cell apoptosis. There were no reports that heat stress damaged spermatogenesis has relationship with androgen. In this study, adult boars (Landrace, n = 9) were used and randomly divided into: control group (CON), 20-27 °C; environmental hyperthermia group (EH), 37-40 °C, 3 h/d 42 d; and local testicular heating group (LTH), 42 °C 1 h. After heat treatments, all boars were castrated and the testes were harvested. qRT-PCR and Western Blot results showed that the mRNA and protein levels of heat shock protein 70 and androgen receptor were significantly increased after heat treatments. Immunohistochemistry results showed that heat stress caused a redistribution of heat shock protein 70 from the cytoplasm to the nucleus, and androgen receptor was mainly expressed in Sertoli cells. These results indicated that heat stress promoted the inhibition of heat shock protein 70 on the androgen receptor, suggesting that the possible mechanism of heat stress damaged spermatogenesis and semen quality was that heat stress reduced the sensitivity of testicular cells to androgen by up-regulating heat shock proteins.

Effects of cold-inducible RNA-binding protein on the proliferation and apoptosis of spermatogenic cells in vitro following heat stress

Cold-inducible RNA-binding protein (CIRBP) is reduced by scrotal hyperthermia in cryptorchidism, varicocoele and heat treatment, but there is no direct evidence clarifying the relationship between CIRBP and spermatogenesis. The aim of this study was to investigate the expression of CIRBP in GC2-spd cells (a mouse spermatocyte cell line) before and after heat treatment, and to determine the effects of the downregulation or overexpression of CIRBP on spermatocyte cell proliferation and apoptosis. GC2-spd cells overexpressing CIRBP and GC2-spd cells in CIRBP was knocked down were constructed to investigate the function of CIRBP in cell proliferation and apoptosis using a cell counting kit-8 and flow cytometry respectively. In addition, proliferation and apoptosis were evaluated in GC2-spd cells that had been heated for 30 or 60min, and were analysed 12, 24, and 48h after heat treatment. Heat treatment clearly suppressed the proliferation of GC2-spd cells, and upregulation of CIRBP expression in GC2-spd cells promoted cell proliferation and decreased apoptosis before and after heat stress; in contrast, downregulation of CIRBP expression inhibited cell proliferation and increased apoptosis. These findings suggest that CIRBP exerts a protective effect against spermatogenic injury caused by heat stress.

The regulation of CIRBP by transforming growth factor beta during heat shock-induced testicular injury

BACKGROUND

Cold-inducible RNA-binding protein (CIRBP) is associated with cell stress. However, its upstream regulatory factors are still largely unknown.

OBJECTIVES

This study investigated whether CIRBP expression was regulated by transforming growth factor beta (TGF-β) during the process of heat-induced testicular damage.

MATERIALS AND METHODS

Ten male adult ICR mice were allocated to heat treatment (scrotal hyperthermia at 43 °C for 30 min, n = 5) and control group (n = 5); CIRBP and TGF-β1, TGF-β2, and TGF-β3 expression levels in the testis in mRNA and protein were analyzed. Then, we conducted in vivo and in vitro studies to investigate the regulatory effects of TGF-β on CIRBP. In the in vivo study, male adult ICR mice were subjected to testicular hyperthermia followed by a local testicular injection of TGF-β antagonist (non-selective TGF-β I/II receptor inhibitor, 5 μg or 10 μg). In the in vitro study, GC2-spd cells were cultured under 43 °C for 30 min or with different TGF-β isoforms (10 ng/mL), and CIRBP expression levels in the testis and GC2-spd cells were analyzed 24 and 48 h, respectively, after treatment.

RESULTS

As a result, heat treatment significantly downregulated the relative CIRBP mRNA and protein expression (p = 0.006 and 0.011), and significantly upregulated TGF-β2 and TGF-β3 expression levels (p = 0.022 and 0.04, for mRNA, and p = 0.001 for both protein levels). Local testicular injection of 10 μg TGF-β antagonist significantly attenuated heat-induced histological damage to the testes and CIRBP downregulation (p = 0.038). Furthermore, TGF-β2 and TGF-β3 significantly downregulated CIRBP mRNA and protein expression in GC2-spd cells (all p < 0.01), exerting a similar effect to heat treatment.

DISCUSSION AND CONCLUSION

Our in vivo and in vitro experiments demonstrated that heat-induced CIRBP downregulation in the testes was mediated by the upregulation of TGF-β. Further studies are needed to clarify the molecular mechanisms underlying these processes.

ERK1/2 regulates heat stress-induced lactate production via enhancing the expression of HSP70 in immature boar Sertoli cells

Lactate produced by Sertoli cells plays an important role in spermatogenesis, and heat stress induces lactate production in immature boar Sertoli cells. Extracellular signaling regulated kinase 1 and 2 (ERK1/2) participates in heat stress response. However, the effect of ERK1/2 on heat stress-induced lactate production is unclear. In the present study, Sertoli cells were isolated from immature boar testis and cultured at 32 °C. Heat stress was induced in a 43 °C incubator for 30 min. Proteins and RNAs were detected by western blotting and RT-PCR, respectively. Lactate production and lactate dehydrogenase (LDH) activity were detected using commercial kits. Heat stress promoted ERK1/2 phosphorylation, showing a reducing trend with increasing recovery time. In addition, heat stress increased heat shock protein 70 (HSP70), glucose transporter 3 (GLUT3), and lactate dehydrogenase A (LDHA) expressions, enhanced LDH activity and lactate production at 2-h post-heat stress. Pretreatment with U0126 (1 × 10-6 mol/L), a highly selective inhibitor of ERK1/2 phosphorylation, reduced HSP70, GLUT3, and LDHA expressions and decreased LDH activity and lactate production. Meanwhile, ERK2 siRNA1 reduced the mRNA level of ERK2 and weakened ERK1/2 phosphorylation. Additionally, ERK2 siRNA1 reduced HSP70, GLUT3, and LHDA expressions decreased LDH activity and lactate production. Furthermore, HSP70 siRNA3 downregulated GLUT3 and LDHA expressions and decreased LDH activity and lactate production. These results show that activated ERK1/2 increases heat stress-induced lactate production by enhancing HSP70 expression to promote the expressions of molecules related to lactate production (GLUT3 and LDHA). Our study reveals a new insight in reducing the negative effect of heat stress in boars.

Changes in Levels of Seminal Nitric Oxide Synthase, Macrophage Migration Inhibitory Factor, Sperm DNA Integrity and Caspase-3 in Fertile Men after Scrotal Heat Stress

Background

This study observes changes in levels of seminal nitric oxide (NO), nitric oxide synthase (NOS), macrophage migration inhibitory factor (MIF), sperm DNA integrity, chromatin condensation and Caspase-3in adult healthy men after scrotal heat stress (SHS).

Methods

Exposure of the scrotum of 25 healthy male volunteers locally at 40–43°C SHS belt warming 40 min each day for successive 2 d per week. The course of SHS was continuously 3 months. Routine semen analysis, hypo-osmotic swelling (HOS) test, Aniline blue (AB) staining, HOS/AB and terminal deoxynucleotidyl transferase-mediated d UDP nick-end labeling (TUNEL) were carried out before, during and after SHS. Seminal NO and NOS contents were determined by nitrate reduction method. The activated Caspase-3 levels of spermatozoa and MIF in seminal plasma were measured by the enzyme-linked immunosorbent assay (ELISA) method. Statistical significance between mean values was determined using statistical ANOVA tests.

Results

The mean parameters of sperm concentration, motile and progressive motile sperm and normal morphological sperm were significantly decreased in groups during SHS 1, 2 and 3 months compared with those in groups of pre-SHS (P<0.001). Statistically significant differences of sperm DNA fragmentation, normal sperm membrane, and Caspase-3 activity as well as the level of NO, NOS and MIF in semen were observed between the groups before SHS and after SHS 3 months and the groups during SHS 1, 2 and 3 months (P<0.001). After three months of the SHS, various parameters recovered to the level before SHS. WBC in semen showed a positively significant correlation with the levels of NO, NOS, MIF and Caspase-3 activity. The percentage of abnormal sperm by using the test of HOS showed a positively significant correlation with that of HOS/AB.

Conclusions

The continuously constant SHS can impact the semen quality and sperm DNA and chromatin, which may be contributed to the high level of NO, NOS, MIF and Caspase-3 by SHS.

Baicalin protects sertoli cells from heat stress-induced apoptosis via activation of the Fas/FasL pathway and Hsp72 expression

Certain Chinese herbal medicines have antipyretic effects in both animal and human clinical practice. However, no report indicates their antipyretic effects on heat-stressed cells. The present study aimed to identify the protective effects of baicalin on the apoptosis of primary cultured bovine sertoli cells (SCs) subjected to heat stress (HS). The results demonstrated that HS induced apoptosis in the SCs exposed to 43°C for 1h as Fas/FasL was activated and caspase-3 was cleaved, the cells apoptotic rate was decreased. Moreover, the mRNA and protein levels of Hsp72 increased, whereas the cells apoptotic rate and expression of Fas, FasL, caspases 8 and 3 decreased in the SCs pretreated with various concentrations (0.1, 1, 10, 20μg/mL) of baicalin prior to HS. In conclusion, baicalin ameliorates heat stress-induced cell apoptosis via the modulation of the cell survival rate through Fas/FasL pathway activation and the upregulation of Hsp72 expression in bovine SCs.

Scrotal heat stress causes sperm chromatin damage and cysteinyl aspartate-spicific proteinases 3 changes in fertile men

PURPOSE

To observe changes in semen parameters, sperm DNA integrity, chromatin condensation and cysteinyl aspartate-spicific proteinases (Caspase-3) in adult healthy men after scrotal heat stress (SHS).

METHODS

The scrotums of 19 healthy male volunteers were exposed to the condition of 40-43 °C SHS belt warming 40 min each day for successive 2 days per week. The course of SHS was continuously 3 months. Routine semen analysis, hypo-osmotic swelling (HOS) test, eosin Y (EY) staining sperm HOS and chromatin dispersion (HOS/SCD) test, HOS and aniline blue (HOS/AB) staining test were carried out before, during and after SHS. The activated Caspase 3 levels of spermatozoa were determined with a microtiter plate reader.

RESULTS

The mean parameters of sperm concentration, motility and normal morphological sperm were significantly decreased in groups with sperm being collected during SHS 1, 2 and 3 months when compared with those in groups of pre-SHS (P < 0.01). Statistically significant differences of sperm DNA fragmentation, normal sperm membrane and vitality, and Caspase-3 activity were observed between the groups of before SHS and after SHS 3 months and the groups of during SHS 1, 2 and 3 months (P < 0.001). Three months the SHS stopped, various parameters recovered to the level before SHS. Abnormal sperm with HOS/AB and HOS/SCD showed a negatively significant correlation with normal sperm by HOS/EY test, and WBC in semen showed a positively significant correlation with Caspase-3 activity. The percentage of abnormal sperm by using the test of HOS/SCD showed a positively significant correlation with that of HOS/AB.

CONCLUSIONS

The continuously constant SHS can impact the semen quality, sperm DNA integrity, chromatin condensation and Caspase-3, and the combination of HOS plus AB test may simultaneously determine the integrity of membrane and chromatin condensation at the same spermatozoon.

Clusterin produced by Sertoli cells inhibits heat stress-induced apoptosis in the rat testis

The objectives of this study were to determine whether the inhibition of clusterin expression in rat Sertoli cells enhances heat stress-induced apoptosis. The scrotums of rats were immersed in a water bath of 43 °C for 15 min. Testicular weight and germ cell number markedly decreased after the heat treatment in a time-dependent manner. In contrast, clusterin mRNA and protein expression levels were significantly up-regulated and peaked on day 21. The apoptotic index was markedly increased 1 day after the heat treatment. We then purified Sertoli cells from the rat testes, and an expression vector containing siRNA targeting the clusterin gene was transiently transfected into Sertoli cells. Following exposure to heat stress at 41 °C for 12 h, clusterin mRNA was markedly up-regulated after transfection with the control vector; however, the transfection of siRNA targeting the clusterin resulted in >70% reduction in the expression of clusterin mRNA. Furthermore, the apoptotic index in these Sertoli cells was significantly higher after the treatment with siRNA targeting the clusterin than control, and the most prominent difference was observed within 24 h after the heat treatment. These results suggest that an increase in the secretion of clusterin by Sertoli cells protects the testes from heat stress-induced injury.

The hypoxic testicle: physiology and pathophysiology

Mammalian spermatogenesis is a complex biological process occurring in the seminiferous tubules in the testis. This process represents a delicate balance between cell proliferation, differentiation, and apoptosis. In most mammals, the testicles are kept in the scrotum 2 to 7°C below body core temperature, and the spermatogenic process proceeds with a blood and oxygen supply that is fairly independent of changes in other vascular beds in the body. Despite this apparently well-controlled local environment, pathologies such as varicocele or testicular torsion and environmental exposure to low oxygen (hypoxia) can result in changes in blood flow, nutrients, and oxygen supply along with an increased local temperature that may induce adverse effects on Leydig cell function and spermatogenesis. These conditions may lead to male subfertility or infertility. Our literature analyses and our own results suggest that conditions such as germ cell apoptosis and DNA damage are common features in hypoxia and varicocele and testicular torsion. Furthermore, oxidative damage seems to be present in these conditions during the initiation stages of germ cell damage and apoptosis. Other mechanisms like membrane-bound metalloproteinases and phospholipase A2 activation could also be part of the pathophysiological consequences of testicular hypoxia.

Heat Shock Protein 72 Protects Kidney Proximal Tubule Cells From Injury Induced by Triptolide by Means of Activation of the MEK/ERK Pathway

Triptolide, which has been used to treat inflammatory diseases, has also been reported to inhibit proliferation of cancer cells. However, it can cause severe nephrotoxicity, limiting its clinical use. Here, nephrotoxicity of triptolide was observed in vivo and in vitro. Heat shock protein 72 (HSP72) was upregulated during kidney injury in rats. HSP72 partially protected human kidney proximal tubule cell lines HK-2 and HKC from triptolide-induced injury. Phospho-Raf, phospho-MEK and phospho-ERK were elevated in HK-2 cells that overexpressed HSP72 after either heat shock or triptolide treatment, and downregulated when HSP72 was repressed by siRNA. The participation of the MEK/ERK1/2 pathway was confirmed by exposure of the cells to the MEK inhibitor U0126. Collectively, our results suggested that HSP72 plays a protective role by means of the MEK/ERK pathway, against triptolide-induced kidney injury.