Lenti-siRNA Hsp60 promote bax in mitochondria and induces apoptosis during heat stress

Overexpression of Acetylation-Defective Heat Shock Protein 60 Inhibits the Proliferation of Nucleopolyhedrovirus in Bombyx mori

Heat shock protein 60 (Hsp60), abundantly presents in mitochondria, is a highly conserved chaperone that maintains the stability and functionality of mitochondrial proteins, while also participating in the regulation of various cellular processes. As a member of the heat shock family, Hsp60 significantly influences viral proliferation. However, limited research is available on its role in the proliferation of entomopathogenic baculoviruses, particularly Bombyx mori nucleopolyhedrovirus (BmNPV). Our previous proteomics results showed a significant decrease of Hsp60 acetylation levels after BmNPV infection. To investigate the impact of Hsp60 deacetylation on viral proliferation, site-direct mutagenesis was performed to generate a deacetylated (K/R) mimic of Hsp60. We found that the acetylation level of lysine 362 (K362) decreased after BmNPV challenge. Furthermore, overexpression of deacetylation-mimicking Hsp60 reduced the chaperone activity of Hsp60, leading to impaired mitochondrial function, including increased reactive oxygen species (ROS) levels, decreased mitochondrial membrane potential, and reduced substrate protein Manganese-containing superoxide dismutase (Mn-SOD) activities, ultimately leading to inhibition of viral proliferation. This study establishes lysine 362 acetylation of Hsp60 as a model for Posttranslational modifications induced by host-virus interactions, providing new insights into potential antiviral strategies.

A new weapon: the application of tumor vaccines based on extracellular exosomal heat shock proteins in immunotherapy

Despite the significant advancements in cancer research, innovative approaches are still needed to reduce tumor incidence, progression, and dissemination, as well as for prolonging patient survival. Currently, the development of cancer vaccines is gaining attention as a novel preventative and therapeutic strategy. Although the concept of cancer vaccination is not new, a limited number of vaccines have received approval for tumor therapy. Heat shock protein (HSP)-based vaccination represents a promising strategy that harnesses specific tumor antigens to activate immune responses. Exosomes (Exs) are highly heterogeneous bilayer vesicles capable of transporting various types of molecules through extracellular space. Compared with conventional anticancer drugs, exosomes exhibit low toxicity and good biocompatibility, and they can stimulate the immune system either directly or indirectly. Ex-based vaccines may elicit an antitumor immune response that generates memory cells capable of recognizing cancer antigens, thereby inhibiting disease progression. This paper reviews the potential applications of HSPs and exosomes in the prevention and treatment of solid tumors. Finally, we discuss the advantages of the extracellular exosomal heat shock protein (HSP-Ex) vaccine and future research directions aimed at optimizing heat shock protein-based cancer immunotherapy strategies.

Mechanism of activation of TLR4/NF-κB/NLRP3 signaling pathway induced by heat stress disrupting the filtration barrier in broiler

BACKGROUND

High-temperature environment can cause acute kidney injury affecting renal filtration function. To study the mechanism of renal injury caused by heat stress through activates TLR4/NF-κB/NLRP3 signaling pathway by disrupting the filtration barrier in broiler chickens. The temperature of broilers in the TN group was maintained at 23 ± 1 °C, and the HS group temperature was maintained at 35 ± 1℃ from the age of 21 days, and the high temperature was 10 h per day, and one broiler from each replicate group at the age of 35 and 42 days was selected for blood sampling, respectively.

RESULTS

The ELISA results demonstrated that in comparison to the TN group, serum CORT content of broilers in the HS group was all remarkably elevated (P < 0.01); the levels of IL-6 and TNF-α in the serum were remarkably elevated (P < 0.05 or P < 0.01); serum CAT and SOD activities were all remarkably reduced (P < 0.05 or P < 0.01), and serum LDH activity and MDA content were all remarkably decreased (P < 0.05); serum BUN and CRE levels were remarkably elevated (P < 0.01). Pathological sections and transmission electron microscopy demonstrated that the structure of the renal filtration barrier in the HS group damaged gradually with the prolongation of heat stress in comparison to the TN group, but the damage was reduced at 42 days of age; the levels of TLR4, MyD88, NF-κB, NF-κB-p65, NLRP3, caspase-1 and IL-1β mRNAs were all up-regulated (P < 0.05 or P < 0.01) in renal tissues of the HS group, indicating that heat stress caused damage to the morphological structure and function of the renal filtration barrier and that TLR4/NF-κB/NLRP3 pathway was also affected by heat stress, leading to increased activity (P < 0.05 or P < 0.01).

CONCLUSIONS

It demonstrated that heat stress caused detrimental effects on both the morphological structure and function of the renal filtration barrier, and the initiation of the TLR4/NF-κB/NLRP3 signaling pathway exacerbated the inflammatory damage, leading to increased thermal damage to renal tissues and glomerular filtration barriers; however, with the prolongation of heat stress, broilers gradually developed heat tolerance, and the damage to the renal tissues and filtration barriers triggered by heat stress was mitigated.

Simultaneous targeting and suppression of heat shock protein 60 to overcome heat resistance and induce mitochondrial death of tumor cells in photothermal immunotherapy

As the most aggressive and metastatic subtype of breast cancer, clinical demands of triple negative breast cancer (TNBC) have far not been met. Heat shock protein 60 (HSP60) is over expressed in tumor cells and impair the efficacy of photothermal therapy. In this work, a conjugate composed of self-designed peptide targeting HSP60 and gold nanorods was constructed, referred to as AuNR-P17. Results showed that AuNR-P17 was able to simultaneously down regulate the level of HSP60 and locate in the mitochondria where HSP60 is enriched in the tumor cells of TNBC, which also impeded the interaction between HSP60 and integrin α3, thereby reducing the tumor cells' heat tolerance and metastatic capabilities. At the same time, AuNR-P17 induced remarkable mitochondrial apoptosis when exposed to the laser irradiation of 808 nm. The dual functions of AuNR-P17 led to the decrement of BCL-2 and the activation of p53 and cleaved caspase-3. The danger associated molecular patterns (DAMPs) generated from the mitochondrial apoptosis elicited strong and long-term specific immune responses against TNBC in vivo and ultimately inhibited the tumor metastasis and recurrence with significantly prolonged survival (>100 days) on TNBC mice. In conclusion, this study demonstrated HSP60 a promising potential therapeutic target for triple negative breast cancer and exhibited powerful capacity of AuNR-P17 in photothermal immune therapy.

HSP90 Enhances Mitophagy to Improve the Resistance of Car-Diomyocytes to Heat Stress in Wenchang Chickens

Heat shock protein 90 (HSP90) is recognized for its protective effects against heat stress damage; however, the specific functions and underlying molecular mechanisms of HSP90 in heat-stressed cardiomyocytes remain largely unexplored, particularly in tropical species. In our study, Wenchang chickens (WCCs) were classified into two groups: the heat stress survival (HSS) group and the heat stress death (HSD) group, based on their survival following exposure to heat stress. Heat stress resulted in significant cardiomyocyte damage, mitochondrial dysfunction, and apoptosis in the HSD group, while the damage was less pronounced in the HSS group. We further validated these findings in primary cardiomyocytes derived from Wenchang chickens (PCWs). Additionally, heat stress was found to upregulate Pink1/Parkin-mediated mitophagy, which was accompanied by an increase in HSP90 expression in both cardiomyocytes and PCWs. Our results demonstrated that HSP90 overexpression enhances PINK1/Parkin-mediated mitophagy, ultimately inhibiting apoptosis and oxidative stress in heat-stressed PCWs. However, the application of Geldanamycin (GA) reversed these effects. Notably, we discovered that HSP90 interacts with Beclin-1 through mitochondrial translocation and directly regulates mitophagy levels in PCWs. In summary, we have elucidated a novel role for HSP90 and mitophagy in regulating heat stress-induced acute cardiomyocyte injury.

The Role of Mitochondrial Permeability Transition in Bone Metabolism, Bone Healing, and Bone Diseases

Bone is a dynamic organ with an active metabolism and high sensitivity to mitochondrial dysfunction. The mitochondrial permeability transition pore (mPTP) is a low-selectivity channel situated in the inner mitochondrial membrane (IMM), permitting the exchange of molecules of up to 1.5 kDa in and out of the IMM. Recent studies have highlighted the critical role of the mPTP in bone tissue, but there is currently a lack of reviews concerning this topic. This review discusses the structure and function of the mPTP and its impact on bone-related cells and bone-related pathological states. The mPTP activity is reduced during the osteogenic differentiation of mesenchymal stem cells (MSCs), while its desensitisation may underlie the mechanism of enhanced resistance to apoptosis in neoplastic osteoblastic cells. mPTP over-opening triggers mitochondrial swelling, regulated cell death, and inflammatory response. In particular, mPTP over-opening is involved in dexamethasone-induced osteoblast dysfunction and bisphosphonate-induced osteoclast apoptosis. In vivo, the mPTP plays a significant role in maintaining bone homeostasis, with many bone disorders linked to its excessive opening. Genetic deletion or pharmacological inhibition of the over-opening of mPTP has shown potential in enhancing bone injury recovery and alleviating bone diseases. Here, we review the findings on the relationship of the mPTP and bone at both the cellular and disease levels, highlighting novel avenues for pharmacological approaches targeting mitochondrial function to promote bone healing and manage bone-related disorders.

Advances in the Effects of Heat Stress on Ovarian Granulosa Cells: Unveiling Novel Ferroptosis Pathways

Heat stress has been one of the key research areas for researchers due to the wide-ranging effects and complex mechanisms of action of its stress product reactive oxygen species (ROS). The aim of this paper is to comprehensively review and summarize the effects of heat stress on ovarian granulosa cells and their mechanism of action. We systematically reviewed the effects of heat stress on ovarian granulosa cells, including intracellular steroid hormone changes, oxidative stress, apoptosis, and mitochondrial function. Meanwhile, this paper discusses in detail several major mechanisms by which heat stress induces apoptosis in ovarian granulosa cells, such as through the activation of apoptosis-related genes, induction of endoplasmic reticulum stress, and the mitochondrial pathway. In addition, we analyzed the mechanism of ferroptosis in ovarian granulosa cells under heat stress conditions, summarized the potential association between heat stress and ferroptosis in light of the existing literature, and explored the key factors in the mechanism of action of heat stress, such as the signaling pathways of Nrf2/Keap1, HSPs, and JNK, and analyzed their possible roles in the process of ferroptosis. Finally, this paper provides an outlook on the future research direction, describing the possible interaction between heat stress and ferroptosis, with a view to providing a theoretical basis for further understanding and revealing the complex mechanism of ferroptosis occurrence in ovarian granulosa cells under heat stress.

The proteomics analysis of extracellular vesicles revealed the possible function of heat shock protein 60 in Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H. pylori) infection is a major risk factor for gastric diseases, including gastritis and gastric cancer. Heat shock protein 60 (HSP60) is a chaperone protein involved in various cellular processes and has been implicated in the immune response to bacterial infections. Extracellular vesicles (EVs) containing various protein components play important roles in cell communication. In the present study, a systematic proteomic analysis of EVs obtained from H. pylori infected cells was performed and the EV-derived HSP60 function was studied.

METHODS

EVs were evaluated by nanoparticle tracking analysis, transmission electron microscopy and western blotting. The recognized protein components were quantified by label-free proteomics and subjected to bioinformatics assays. The expression of HSP60 in EVs, host cells and gastric cancers infected by H. pylori was determined by western blotting and immunohistochemical, respectively. In addition, the apoptotic regulation mechanisms of HSP60 in H. pylori infection were analyzed by western blotting and flow cytometry.

RESULTS

A total of 120 important differential proteins were identified in the EVs from H. pylori-infected cells and subjected to Gene Ontology analysis. Among them, CD63, HSP-70 and TSG101 were verified via western blotting. Moreover, HSP60 expression was significantly increased in the EVs from H. pylori-infected GES-1 cells. H. pylori infection promoted an abnormal increase in HSP60 expression in GES-1 cells, AGS cells, gastric mucosa and gastric cancer. In addition, knockdown of HSP60 suppressed the apoptosis of infected cells and the expression of Bcl2, and promoted the upregulation of Bax.

CONCLUSION

This study provides a comprehensive proteomic profile of EVs from H. pylori-infected cells, shedding light on the potential role of HSP60 in H. pylori infection. The findings underscore the significance of EV-derived HSP60 in the pathophysiology of H. pylori-associated diseases.

Impact of Non-Invasive Physical Plasma on Heat Shock Protein Functionality in Eukaryotic Cells

Recently, biomedical research has increasingly investigated physical plasma as an innovative therapeutic approach with a number of therapeutic biomedical effects. It is known from radiation and chemotherapy that these applications can lead to the induction and activation of primarily cytoprotective heat shock proteins (HSP). HSP protect cells and tissues from physical, (bio)chemical, and physiological stress and, ultimately, along with other mechanisms, govern resistance and treatment failure. These mechanisms are well known and comparatively well studied in drug therapy. For therapies in the field of physical plasma medicine, however, extremely little data are available to date. In this review article, we provide an overview of the current studies on the interaction of physical plasma with the cellular HSP system.

FOXG1 improves mitochondrial function and promotes the progression of nasopharyngeal carcinoma

Forkhead‑box gene 1 (FOXG1) has been reported to serve an important role in various malignancies, but its effects on nasopharyngeal cancer (NPC) remain unknown. Thus, the present study aimed to investigate the specific regulatory relationship between FOXG1 and NPC progression. Tumor tissues and matching para‑carcinoma tissues were obtained from patients with NPC. Small interfering (si)RNA‑FOXG1 and pcDNA3.1‑FOXG1 were transfected into SUNE‑1 and C666‑1 cells to knockdown and overexpress FOXG1 expression, respectively. FOXG1 expression was detected using reverse transcription‑quantitative PCR and immunohistochemistry. Cell proliferation was detected using MTT and 5‑ethynyl‑20‑deoxyuridine assays. Transwell invasion assay, wound healing assay and flow cytometry were used to detect cell invasion, migration and apoptosis, respectively. Western blotting was conducted to detect the expression levels of mitochondrial markers (succinate dehydrogenase complex flavoprotein subunit A, heat shock protein 60 and pyruvate dehydrogenase), epithelial‑mesenchymal transition (EMT) related proteins (N‑cadherin, Snail and E‑cadherin) and apoptosis‑related proteins [Bax, Bcl‑2, poly(ADP‑ribose) polymerase 1 (PARP), cleaved PARP, cleaved caspase‑3, cleaved caspase‑8, cleaved caspase‑9, caspase‑3, caspase‑8 and caspase‑9]. The mitochondrial membrane potential was detected via flow cytometry, while the ATP/ADP ratio was determined using the ADP/ATP ratio assay kit. The present results demonstrated that FOXG1 expression was upregulated in NPC tissues and cells, and was associated with distant metastasis and TNM stage. Moreover, knockdown of FOXG1 inhibited the proliferation, migration, invasion, EMT and mitochondrial function of SUNE‑1 cells, as well as promoted cell apoptosis, while the opposite results were observed in C666‑1 cells. In conclusion, FOXG1 enhanced proliferation, migration and invasion, induced EMT and improved mitochondrial function in NPC cells. The current findings provide an adequate theoretical basis for the treatment of NPC.

Central role of TRAP1 in the ameliorative effect of oleanolic acid on the mitochondrial-mediated and endoplasmic reticulum stress-excitated apoptosis induced by ochratoxin A

Ochratoxin A (OTA) is a nephrotoxic mycotoxin that is widely distributed in foodstuffs and feeds, meanwhile oleanolic acid (OA) is ubiquitous in various fruit skins, food materials, and medicinal herbs. Due to that OA has a nephroprotective effect, it has the poteintial to counteract OTA-induced nephrotoxicity by nutritional intervention of OA. Furthermore, tumor necrosis factor receptor-associated protein 1 (TRAP1) acts as the core of endoplasmic reticulum (ER)-mitochondria crosstalk, becoming our focus in the mechanism investigation. In this study, the cell viability, apoptosis rate, and protein expressions of human proximal tubule epithelial-originated kidney-2 (HK-2) cells in response to OTA and/or OA were determined. Results indicated that a 24 h-treatment of 1-5 μM OTA could notably induce mitochondrial-mediated and ER stress (ERS)-excitated apoptosis via inhibiting TRAP1, thereby activating CypD, Bax, Cyt-C, Cleaved Caspase-9, Cleaved Caspase-3, GRP78, p-PERK, p-eIF2α, ATF4, and CHOP and inhibiting Bcl-2 (P < 0.05). Results of the RNA interference of TRAP1 further ascertained its anti-apoptotic function via inhibiting CypD, Bax, GRP78, and CHOP and enhancing Bcl-2 (P < 0.05). The pre-treatment of 2 μM OA for 2 h could remarkably relieve OTA-induced suppression of TRAP1 (P < 0.05). In conclusion, TRAP1 played a central role in the ameliorative effect of OA on the mitochondrial-mediated and ERS-excitated apoptosis induced by OTA.

Abnormal lipid metabolism induced apoptosis of spermatogenic cells by increasing testicular HSP60 protein expression

Long-term consumption of high-fat and high-calorie foods not only causes obesity, but also may cause a decline in sperm quality in men. Rats with abnormal lipid metabolism (high-fat rats) were established by high-fat diet for 24 weeks. HE staining was used to observe the morphological changes of testis in rats, TUNEL and flow cytometer was used to detect the cell apoptosis in rat testis and in vitro. Immunohistochemistry and Western blotting were used to detect the expression of protein. After 24 weeks of high-fat food feeding, the body weight, serum lipids and number of apoptotic spermatogenic cells in the high-fat group rat were significantly higher than those in the control group. In vivo, the expression of HSP60 protein in testis of high-fat rats was positive related to apoptosis of spermatogenic cells, cleaved caspase 3/caspase 3 protein expression and Bax/Bcl2 protein expression in testis of high-fat rats. Proportion of apoptotic spermatogenic cells was increased by up-regulation of HSP60 protein expression in vitro. Long-term consumption of high-fat diets can cause high expression of HSP60 and spermatogenic cells apoptosis in rats, while HSP60 over-expression promotes spermatogenic cell apoptosis and MAPK signal pathway in vitro.

Heat shock protein 60 and cardiovascular diseases: An intricate love-hate story

Cardiovascular diseases (CVDs) are the result of complex pathophysiological processes in the tissues comprising the heart and blood vessels. Inflammation is the main culprit for the development of cardiovascular dysfunction, and it may be traced to cellular stress events including apoptosis, oxidative and shear stress, and cellular and humoral immune responses, all of which impair the system's structure and function. An intracellular chaperone, heat shock protein 60 (HSP60) is an intriguing example of a protein that may both be an ally and a foe for cardiovascular homeostasis; on one hand providing protection against cellular injury, and on the other triggering damaging responses through innate and adaptive immunity. In this review we will discuss the functions of HSP60 and its effects on cells and the immune system regulation, only to later address its implications in the development and progression of CVD. Lastly, we summarize the outcome of various studies targeting HSP60 as a potential therapeutic strategy for cardiovascular and other diseases.

Lactic acid accumulation under heat stress related to accelerated glycolysis and mitochondrial dysfunction inhibits the mycelial growth of Pleurotus ostreatus

High temperature is a major threat to Pleurotus ostreatus cultivation. In this study, a potential mechanism by which P. ostreatus mycelia growth is inhibited under heat stress was explored. Lactate, as a microbial fermentation product, was found unexpectedly in the mycelia of P. ostreatus under heat stress, and the time-dependent accumulation and corresponding inhibitory effect of lactate on mycelial growth was further confirmed. The addition of a glycolysis inhibitor, 2-deoxy-D-glucose (2DG), reduced the lactate content in mycelia and slightly restored mycelial growth under high-temperature conditions, which indicated the accumulation of lactate can be inhibited by glycolysis inhibition. Further data revealed mitochondrial dysfunction under high-temperature conditions, with evidence of decreased oxygen consumption and adenosine triphosphate (ATP) synthesis and increased reactive oxygen species (ROS). The removal of ROS with ascorbic acid decreased the lactate content, and mycelial growth recovered to a certain extent, indicating lactate accumulation could be affected by the mitochondrial ROS. Moreover, metabolic data showed that glycolysis and the tricarboxylic acid cycle were enhanced. This study reported the accumulation of lactate in P. ostreatus mycelia under heat stress and the inhibitory effect of lactate on the growth of mycelia, which might provide further insights into the stress response mechanism of edible fungi. Key Points • Lactate can accumulate in Pleurotus ostreatus mycelia under heat stress and inhibit its growth. • The accumulation of lactate may be due to the acceleration of glycolysis and the dysfunction of mitochondria of P. ostreatus mycelia under high-temperature stress. • The glycolysis and tricarboxylic acid cycle of P. ostreatus mycelia were accelerated under high-temperature stress.

Ginkgo Biloba Extract in Ophthalmic and Systemic Disease, With a Focus on Normal-Tension Glaucoma

Glaucoma is a neurodegenerative eye disease that results in retinal ganglion cell loss and ultimately loss of vision. Elevated intraocular pressure (IOP) is the most common known risk factor for retinal ganglion cell damage and visual field loss, and the only modifiable risk factor proven to reduce the development and progression of glaucoma. This has greatly influenced our approach and assessment in terms of diagnosis and treatment. However, as many as ≥50% of patients with progressive vision loss from primary open angle glaucoma without IOP elevation (≤22 mm Hg) have been reported in the United States and Canada; 90% in Japan and 80% in Korea. Extensive research is currently underway to identify the etiology of risk factors for glaucoma other than or in addition to elevated IOP (so-called "normal-tension" glaucoma; NTG) and use this knowledge to expand available treatment options. Currently, Food and Drug Administration-approved medications for glaucoma exclusively target elevated IOP, suggesting the need for additional approaches to treatment options beyond the current scope as the definition of glaucoma changes to encompass cellular and molecular mechanisms. This review focuses on alternative medical approaches, specifically Ginkgo Biloba extract, as a potential treatment option for normal-tension glaucoma.

Molecular hydrogen suppresses superoxide generation in the mitochondrial complex I and reduced mitochondrial membrane potential

Molecular hydrogen (H₂) is recognized as a medical gas applicable to numerous diseases including neurodegenerative diseases, metabolic disorders, and rheumatoid arthritis. Although the efficacy of H₂ is reportedly attributed to its scavenging capability against the hydroxyl radical, the mechanisms underlying its therapeutic efficacy are not fully understood. Herein, we estimated the role of H₂ in the energy converting system of the mitochondria, the source of reactive oxygen species. To investigate the effects of H₂ on mitochondrial function, direction of electron flow, superoxide generation, and mitochondrial membrane potential were investigated. Forward electron transport (FET) or reverse electron transport (RET) was assessed by monitoring the decrease or increase of β-nicotinamide adenine dinucleotide hydrate (NADH, - or +, μM, respectively) in the presence of β-nicotinamide adenine dinucleotide (NAD⁺) and/or succinate in the isolated mitochondria. H₂O₂ converted from superoxide by superoxide dismutase (SOD) was measured to estimate electron leakage in the mitochondria. The effects of H₂ on mitochondrial membrane potential were observed by staining cells with the fluorescence probe, teramethylrhodamine ethyl ester (TMRE). Despite the absence of succinate, a distinct RET was observed (from +0.0313 ± 0.0106 μM to +1.20 ± 0.302 μM) by adding 25 μM H₂. In the presence of 5 μM NADH, RET by succinate inverted to FET from +1.62 ± 0.358 μM to -1.83 ± 0.191 μM, accompanied by a suppression of superoxide generated predominantly from complex I by 51.1%. H₂ solely reduced mitochondrial membrane potential of the cultured cells by 11.3% as assessed by TMRE. The direction of electron flow was altered by H₂ depending on the NAD⁺/NADH ratio, accompanied by suppression of superoxide generation H₂ could suppress superoxide generation in complex I in vitro and reduce membrane potential in vivo. H₂ may also neutralize semiquinone radicals to reduce superoxide produced in complex III. H₂ may function as a rectifier of the electron flow affecting the mitochondrial membrane potential to suppress oxidative damage in mitochondria.

Vitamin C mitigates heat damage by reducing oxidative stress, inducing HSP expression in TM4 Sertoli cells

Heat stress is a major stressor that can lead to male reproductive dysfunction. Sertoli cells play a crucial role in spermatogenesis by providing germ cells with structural and nutritional support, and contributing to blood-testis barrier formation. Vitamin C (Vc) is an antioxidant capable of neutralizing reactive oxygen species and preventing lipid peroxidation widely used because it is inexpensive and highly accessible. In the present study, we investigated the protective effect of Vc on TM4 cells following heat stress. Pretreatment with Vc could effectively inhibit apoptosis (p < 0.01), lipid peroxidation, and lactate dehydrogenase (LDH) activity. However, a significant increase in the malondialdehyde (MDA) level and LDH activity (p < 0.01) was observed in TM4 cells without Vc-pretreatment, in conjunction with vacuole degeneration and karyopyknosis. In addition, both the messenger RNA and protein levels of CryAB, Hsp27, Hsp70, and Hsp110 substantially increased in the 3 and 12 hr recovery groups (p < 0.01). Vc also prevented microtubule aggregation following heat stress. These results suggest that pretreatment with Vc-protected TM4 cells against heat stress by reducing the level of oxidative stress and inducing heat shock protein expression.

Heat stress-induced renal damage in poultry and the protective effects of HSP60 and HSP47

The present study investigates the effects of heat stress on the kidney in broilers, based on previous findings which showed that heat stress caused cardiac damage in broilers. Further, the possible renoprotective role of aspirin and the heat shock proteins HSP60 and HSP47 was also investigated. The enzyme levels of urea and uric acid, which are indicators of renal damage, and lactate dehydrogenase, an indicator of oxidative damage, were measured in chickens that were only exposed to heat stress, chickens that were pretreated with aspirin before heat stress, and chickens that were only treated with aspirin. Further, histological examination of renal tissue from the three groups was also performed. Finally, expression of HSP60 and HSP47 was also examined. In the heat stress group, the enzyme measurements were indicative of renal dysfunction and oxidative damage, and the histological findings were indicative of renal ischemia and damage. Aspirin seemed to have a protective effect against the renal damage caused by the stress, based on the enzyme measurements and histopathological findings in the aspirin-treated group. The findings also indicate that aspirin may induce HSP60 and HSP47 expression in renal cells. Finally, the expression patterns of HSP60 and HSP47 indicated that they may play a renoprotective role, as their expression was higher in the aspirin-treated groups. In conclusion, the present findings show that heat stress causes renal damage in poultry and that aspirin may play a protective role against this damage via pathways that involve HSP60 and HSP47.

Vitamin C and sodium bicarbonate enhance the antioxidant ability of H9C2 cells and induce HSPs to relieve heat stress

Heat stress is exacerbated by global warming and affects human and animal health, leading to heart damage caused by imbalances in reactive oxygen species (ROS) and the antioxidant system, acid-base chemistry, electrolytes and respiratory alkalosis. Vitamin C scavenges excess ROS, and sodium bicarbonate maintains acid-base and electrolyte balance, and alleviates respiratory alkalosis. Herein, we explored the ability of vitamin C alone and in combination with equimolar sodium bicarbonate (Vitamin C-Na) to stimulate endogenous antioxidants and heat shock proteins (HSPs) to relieve heat stress in H9C2 cells. Control, vitamin C (20 μg/ml vitamin C for 16 h) and vitamin C-Na (20 μg/ml vitamin C-Na for 16 h) groups were heat-stressed for 1, 3 or 5 h. Granular and vacuolar degeneration, karyopyknosis and damage to nuclei and mitochondria were clearly reduced in treatment groups, as were apoptosis, lactate dehydrogenase activity and ROS and malondialdehyde levels, while superoxide dismutase activity was increased. Additionally, CRYAB, Hsp27, Hsp60 and Hsp70 mRNA levels were upregulated at 3 h (p < 0.01), and protein levels were increased for CRYAB at 0 h (p < 0.05) and 1 h (p < 0.01), and for Hsp70 at 3 and 5 h (p < 0.01). Thus, pre-treatment with vitamin C or vitamin C-Na might protect H9C2 cells against heat damage by enhancing the antioxidant ability and upregulating CRYAB and Hsp70.

Moderate High Temperature Condition Induces the Lactation Capacity of Mammary Epithelial Cells Through Control of STAT3 and STAT5 Signaling

In lactating mammary glands, alveolar mammary epithelial cells (MECs) synthesize and secrete milk components. MECs also form less permeable tight junctions (TJs) to prevent the leakage of milk components. During lactation, MECs are exposed to temperature changes by metabolic heat production and air ambient temperature. In this study, we investigated whether temperature changes influence milk production ability and TJ barriers in MECs by using two lactating culture models. The results showed that 39 °C treatment activated milk production and enhanced the formation of less-permeable TJs. In contrast, 41 °C treatment caused adverse effects on the TJ barrier and cell viability, although the milk production ability of MECs was temporarily up-regulated. MECs cultured at 37 °C showed relatively low milk production ability and high proliferation activity. Furthermore, we investigated three kinds of transcription factors relating to lactogenesis, signal transducer and activator of transcription 5 (STAT5), STAT3 and glucocorticoid receptor (GR). STAT5 signaling was activated at 39 and 41 °C by an increase in total STAT5. However, long-term treatment led to a decrease in total STAT5. STAT3 signaling was inactivated by high temperature treatment through a decrease in total STAT3 and inhibited phosphorylation of STAT3. GR signaling was continuously activated regardless of temperature. These results indicate that a moderate high temperature condition at 39 °C induces a high lactation capacity of MECs through control of STAT5 and STAT3 signaling. In contrast, long-term exposure at 41 °C leads to a decline in milk production capacity by inactivation of STAT5 and a decrease in the total number of MECs.