Heat shock proteins in porcine ovary: synthesis, accumulation and regulation by stress and hormones

Abstract

The present studies aimed to understand the interrelationships between stress, hormones and heat shock proteins (HSPs) in the ovary. We examined (1) whether HSP70.2, HSP72 and HSP105/110 can be produced and accumulated in porcine ovarian tissue, (2) whether these HSPs could be indicators of stress, i.e. whether two kinds of stress (high temperatures and malnutrition/serum deprivation) can affect them, and (3) whether some hormonal regulators of ovarian functions (insulin-like growth factor (IGF)-I, leptin and follicle-stimulating hormone (FSH)) can affect these HSPs and response of ovaries to HSP-related stress. We analysed the expression of HSP70.2, HSP72 and HSP105/110 mRNA (by using real-time reverse transcriptase polymerase chain reaction) in porcine ovarian granulosa cells, as well as the accumulation of HSP70 protein (by using sodium dodecyl sulphate polyacrylamide gel electrophoresis-Western) in either whole ovarian follicles and granulose cells cultured at normal (37.5°C) or high (41.5°C) temperature, with and without serum and with and without IGF-I, leptin and FSH. Expression of mRNA for HSP70.2, HSP72 and HSP105/110 in ovarian granulosa cells and accumulation of HSP70 protein in whole ovarian follicles and granulosa cells were demonstrated. In all the groups, addition of either IGF-I, leptin and FSH reduced the expression of HSP70.2, HSP72 and HSP105/110 mRNA. Both high temperature, serum deprivation and their combination resulted in increase in mRNAs for all three analysed HSPs. Additions of either IGF-I, leptin and FSH prevented the stimulatory effect of both high temperature and serum deprivation on the transcription of HSP70.2, HSP72 and HSP105/110. In contrast, high temperature reduced accumulation of peptide HSP70 in both ovarian follicles and granulosa cell. Serum deprivation promoted accumulation of HSP70 in granulosa cells, but not in ovarian follicles. Addition of IGF-I, leptin and FSH was able to alter accumulation of HSP70 in both follicles and granulosa cells. The present observations suggest (1) that HSPs can be synthesised in ovarian follicular granulosa cells; (2) that hormones (IGF-I, leptin and FSH) can inhibit, whilst stressors (both high temperature and malnutrition/serum deprivation) can stimulate transcription of HSP70.2, HSP72 and HSP105/ 110 genes, whilst heat stress, but not malnutrition, can promote depletion of HSP70 in ovarian cells, and (3) that hormones (IGF-I, leptin and FSH) can prevent stress-related changes in HSPs. The application of HSPs as indicators and mediators of stress and hormones on ovarian functions, as well as use of hormones and HSPs as anti-stressor molecules, are discussed.

The effect of heat stress on gene expression, synthesis of steroids, and apoptosis in bovine granulosa cells

“…In all HSPs, the most pronounced stressrelated changes and involvement in granulosa cell functions have been demonstrated for HSP70, and small HSP-HSP32 (HMOX1, HO-1). The high temperature can stimulate the transcription of HSP70.2, HSP72, and HSP105/110 genes in ovarian follicular granulosa cells (Sirotkin 2010;Sirotkin et al 2011). Inducible HO-1 is likely to be important autocrine/ paracrine factors that regulate apoptosis in porcine GCs (Harada et al 2004).…”

The global effect of heat on gene expression in cultured bovine mammary epithelial cells

“…In these genes, highly differential expression was observed for HSPA1A (heat shock 70 kDa protein 1A, 5.9-fold induction) and HSPB8 (heat shock 22 kDa protein 8, 6.3-fold induction). In all HSPs, the most pronounced stress-related changes and involvement in different cell functions have been demonstrated for HSP70 (Grover 2002;Jego et al 2010;Sirotkin and Bauer 2011). The bovine two-cell embryo is capable of increasing transcription of HSPA1A and synthesis of HSP70 in response to heat shock (Sakatani et al 2013).…”

Interaction between the inducible 70-kDa heat shock protein and autophagy: effects on fertility and pregnancy

“…In knockout mice lacking tuberous sclerosis complex 1 (Tsc1), a suppressor of mTORC1 in oocytes, primordial follicles are activated too early leading to a phenotype similar to human premature ovarian failure (Adhikari et al 2010). Elevated temperature as well as malnutrition has been shown to induce hsp70 gene transcription in porcine ovaries (Sirotkin and Bauer 2011). It can also be envisioned that sterile or infection-induced ovarian inflammation may lead to hsp70 induction with a consequent reduction in autophagy and reduced oocyte viability.…”