In vitro evaluation of aspirin-induced HspB1 against heat stress damage in chicken myocardial cells

The consequences of climate change and male reproductive health: A review of the possible impact and mechanisms

A global decline in male fertility has been reported, and climate change is considered a major cause of this. Climate change refers to long-term shifts in temperatures and weather patterns, and results from greenhouse gas emissions like carbon dioxide and methane that act as a blanket wrapped around the earth, trapping heat and elevating temperatures. Sad to say, the consequences of climatic variation are beyond the dramatic elevated temperature, they include cold stress, increased malnutrition, air pollution, cardiovascular diseases respiratory tract infections, cancer, sexually transmitted infections, mental stress, and heat waves. These negative effects of climate change impair male reproductive function through multiple pathways, like ROS-sensitive signaling, suppression of steroidogenic markers, and direct damage to testicular cells. The present study aimed to describe the impact of the consequences of climate change on male reproductive health with details of the various mechanisms involved. This will provide an in-depth understanding of the pathophysiological and molecular basis of the possible climatic variation-induced decline in male fertility, which will aid in the development of preventive measures to abate the negative effects of climate change on male reproductive function.

HSP47 in human diseases: Navigating pathophysiology, diagnosis and therapy

Heat shock protein 47 (HSP47) is a chaperone protein responsible for regulating collagen maturation and transport, directly impacting collagen synthesis levels. Aberrant HSP47 expression or malfunction has been associated with collagen-related disorders, most notably fibrosis. Recent reports have uncovered new functions of HSP47 in various cellular processes. Hsp47 dysregulation in these alternative roles has been linked to various diseases, such as cancer, autoimmune and neurodegenerative disorders, thereby highlighting its potential as both a diagnostic biomarker and a therapeutic target. In this review, we discuss the pathophysiological roles of HSP47 in human diseases, its potential as a diagnostic tool, clinical screening techniques and its role as a target for therapeutic interventions.

The Protective Role of Heat Shock Proteins against Stresses in Animal Breeding

Heat shock proteins (HSPs) play an important role in all living organisms under stress conditions by acting as molecular chaperones. The expression of different HSPs during stress varies depending on their protective functions and anti-apoptotic activities. The application of HSPs improves the efficiency and decreases the economic cost of animal breeding. By upregulating the expression of HSPs, feed supplements can improve stress tolerance in farm animals. In addition, high expression of HSPs is often a feature of tumor cells, and inhibiting the expression of HSPs is a promising novel method for killing these cells and treating cancers. In the present review, the findings of previous research on the application of HSPs in animal breeding and veterinary medicine are summarized, and the knowledge of the actions of HSPs in animals is briefly discussed.

The pathogenesis and therapeutic strategies of heat stroke-induced myocardial injury

Heat stroke (HS) is a febrile illness characterized by an elevation in the core body temperature to over 40°C, accompanied by central nervous system impairment and subsequent multi-organ dysfunction syndrome. In recent years, the mortality rate from HS has been increasing as ambient temperatures continue to rise each year. The cardiovascular system plays an important role in the pathogenesis process of HS, as it functions as one of the key system for thermoregulation and its stability is associated with the severity of HS. Systemic inflammatory response and endothelial cell damage constitute pivotal attributes of HS, other factors such as ferroptosis, disturbances in myocardial metabolism and heat shock protein dysregulation are also involved in the damage to myocardial tissue in HS. In this review, a comprehensively detailed description of the pathogenesis of HS-induced myocardial injury is provided. The current treatment strategies and the promising therapeutic targets for HS are also discussed.

Effects of Zinc Source and Level on the Intestinal Immunity of Xueshan Chickens under Heat Stress

Heat stress can cause intestinal inflammation, impaired barrier integrity, and decreased immunity in poultry. While zinc is known to mitigate the adverse effects of heat stress, how the dietary supplementation of different sources and levels of it can improve the heat stress capacity of Chinese landraces remains unclear. This study investigated Xueshan chickens, which are an important local breed in China. The effects of different levels of ZnS and Zn-Prot M on their intestinal immune function under heat stress were compared. We found that different levels of ZnS and Zn-Prot M could effectively reduce the secretion level of IL-6 in the serum, and 60 mg/kg was optimal. Compared with ZnS, Zn-Prot M significantly increased duodenal villus height and VH/CD ratio, thus Zn-Prot M was more effective than ZnS. Both ZnS and Zn-Prot M significantly down-regulated TNF-α, IL-1β, and MyD88 in 102-day-old duodenum, and IL-1β, IL-6, and NFKBIA in jejunum and ileum at 74, 88, and 102 days old, with 60 mg/kg Zn-Prot M determined as optimal. In conclusion, our study demonstrates that Zn-Prot M is superior to ZnS in improving intestinal immunity in Xueshan chickens, and 60 mg/kg is the optimal addition dose.

House ammonia exposure causes alterations in microbiota, transcriptome, and metabolome of rabbits

Introduction

Pollutant gas emissions in the current production system of the livestock industry have negative influences on environment as well as the health of farm staffs and animals. Although ammonia (NH3) is considered as the primary and harmful gas pollutant in the rabbit farm, less investigation has performed to determine the toxic effects of house ammonia exposure on rabbit in the commercial confined barn.

Methods

In this study, we performed multi-omics analysis on rabbits exposed to high and low concentration of house ammonia under similar environmental conditions to unravel the alterations in nasal and colonic microbiota, pulmonary and colonic gene expression, and muscular metabolic profile.

Results and discussion

The results showed that house ammonia exposure notably affected microbial structure, composition, and functional capacity in both nasal and colon, which may impact on local immune responses and inflammatory processes. Transcriptome analysis indicated that genes related to cell death (MCL1, TMBIM6, HSPB1, and CD74) and immune response (CDC42, LAMTOR5, VAMP8, and CTSB) were differentially expressed in the lung, and colonic genes associated with redox state (CAT, SELENBP1, GLUD1, and ALDH1A1) were significantly up-regulated. Several key differentially abundant metabolites such as L-glutamic acid, L-glutamine, L-ornithine, oxoglutaric acid, and isocitric acid were identified in muscle metabolome, which could denote house ammonia exposure perturbed amino acids, nucleotides, and energy metabolism. In addition, the widespread and strong inter-system interplay were uncovered in the integrative correlation network, and central features were confirmed by in vitro experiments. Our findings disclose the comprehensive evidence for the deleterious effects of house ammonia exposure on rabbit and provide valuable information for understanding the underlying impairment mechanisms.

Targeting HSP47 and HSP70: promising therapeutic approaches in liver fibrosis management

Liver fibrosis is a liver disease in which there is an excessive buildup of extracellular matrix proteins, including collagen. By regulating cytokine production and the inflammatory response, heat shock proteins (HSPs) contribute significantly to a wider spectrum of fibrotic illnesses, such as lung, liver, and idiopathic pulmonary fibrosis by aiding in the folding and assembly of freshly synthesized proteins, HSPs serve as chaperones. HSP70 is one of the key HSPs in avoiding protein aggregation which induces its action by sending unfolded and/or misfolded proteins to the ubiquitin–proteasome degradation pathway and antagonizing influence on epithelial-mesenchymal transition. HSP47, on the other hand, is crucial for boosting collagen synthesis, and deposition, and fostering the emergence of fibrotic disorders. The current review aims to provide light on how HSP70 and HSP47 affect hepatic fibrogenesis. Additionally, our review looks into new therapeutic approaches that target HSP70 and HSP47 and could potentially be used as drug candidates to treat liver fibrosis, especially in cases of comorbidities.

TMT-labeled quantitative proteomic analysis to identify proteins associated with the stability of peanut milk

BACKGROUND

Peanut milk benefits human health mainly due to its high protein content and suitable amino acid composition. To reveal the molecular mechanism affecting the quality of peanut milk, tandem mass tag (TMT)-labeled proteomic analysis was applied to identify the proteome variation between two peanut cultivars that produced peanut milk with the best and worst stability.

RESULTS

A total of 478 differentially abundant proteins (fold change >1.2 or <0.83, P < 0.05) were identified. Most of these proteins were located in the cytoplasm and chloroplasts. Correlation analysis showed that RNA recognition motif (RRM) domain-containing protein (17.1 kDa) had a negative relationship with the sedimentation rate of peanut milk and that 22.0 kDa class IV heat shock protein was negatively correlated with the creaming index (P < 0.05). Bioinformatic analysis showed that the molecular function of RRM domain-containing protein (17.1 kDa) was associated with RNA binding and nucleotide binding, and 22.0 kDa class IV heat shock protein was involved in the pathway of protein processing in the endoplasmic reticulum.

CONCLUSION

Overall, the differentially abundant proteins in the biological metabolic pathway might offer some potential markers to guide future peanut breeding, especially for the production of peanut milk. © 2021 Society of Chemical Industry.

HSF1 and GM-CSF expression, its association with cardiac health, and assessment of organ function during heat stress in crossbred Jersey cattle

The study aimed to evaluate the differential expression of HSF1 and GM-CSF mRNA in PBMCs and correlate it with myocardial injury in crossbred Jersey heifers during heat stress. The study also assessed the effect of heat stress on cardiac electrical activity, vascular health, liver function and kidney function. The experiment was conducted in two phases: for heat stressed animals; HS in June (THI ranged from 80.0 to 89.8) and for control group i.e. not exposed to heat stress in January (THI ranged between 70.1 and 71.4). Results of the study revealed that the relative abundance of HSF1 and GM-CSF mRNA increased significantly (P < 0.05) in HS. Serum cardiac biomarkers such as CK-MB, AST and CRP were significantly elevated (P < 0.05) in HS. cTnI was detected 'positive' in nineteen out of twenty four cases in HS. Correlation of HSF1 and GM-CSF expression with concentration of LDH, CKMB, CRP and AST in HS was negative but non-significant (P > 0.05). Significant (P < 0.05) ECG findings in HS were increased heart rate, decreased RR interval, decreased PR interval, decreased QRS amplitude and decreased amplitude of P wave. Marked reduction (P < 0.05) in serum cholesterol and triglyceride levels was observed in HS. ALP, AST, bilirubin and urea levels in serum were significantly elevated (P < 0.05) in HS. In conclusion, cardiac enzymes in serum were significantly elevated in HS indicating myocardial injury. HSF1 and GM-CSF mRNA expression alone was inadequate in conferring cytoprotection to cardiac cells in HS. Cardiac electrical activity, vascular status, liver and kidney function were significantly altered in HS.

Genome-wide identification and functional prediction of long non-coding RNAs in Sprague-Dawley rats during heat stress

Background

Heat stress (HS) is a major stress event in the life of an animal, with detrimental upshots in production and health. Long-non-coding RNAs (lncRNAs) play an important role in many biological processes by transcriptional regulation. However, no research has been reported on the characterization and functionality of lncRNAs in heat-stressed rats.

Results

We studied expression levels of lncRNAs in rats during HS, using strand-specific RNA sequencing. Six rats, three in each of Control (22 ± 1 °C) and H120 (42 °C for 120 min) experimental groups, were used to screen for lncRNAs in their liver and adrenal glands. Totally, 4498 and 7627 putative lncRNAs were identified in liver and adrenal glands of the Control and H120 groups, respectively. The majority of lncRNAs were relatively shorter and contained fewer exons than protein-coding transcripts. In total, 482 (174 up-regulated and 308 down-regulated) and 271 (126 up-regulated and 145 down-regulated) differentially-expressed lncRNAs (DElncRNAs, P < 0.05) were identified in the liver and adrenal glands of the Control and H120 groups, respectively. Furthermore, 1274, 121, and 73 target differentially-expressed genes (DEGs) in the liver were predicted to interact with DElncRNAs based on trans−/cis- and sequence similarity regulatory modes. Functional annotation analyses indicated that these DEGs were mostly significantly enriched in insulin signalling, myeloid leukaemia, and glucagon signalling pathways. Similarly, 437, 73 and 41 target DEGs in the adrenal glands were mostly significantly enriched in the cell cycle (trans-prediction) and lysosome pathways (cis-prediction). The DElncRNAs interacting with DEGs that encode heat shock proteins (HSPs) may play an important role in HS response, which include Hsf4, Dnaja1, Dnajb4, Hsph1 and Hspb1 in the liver, and Dnajb13 and Hspb8 in the adrenal glands. The strand-specific RNA sequencing findings were also further verified through RT-qPCR.

Conclusions

This study is the first to provide a detailed characterization and functional analysis of expression levels of lncRNAs in liver and adrenal glands of heat-stressed rats, which provides basis for further studies on the biological functions of lncRNAs under heat stress in rats and other mammalian species.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07421-8.

Modulation of Heat-Shock Proteins Mediates Chicken Cell Survival against Thermal Stress

Heat stress is one of the most challenging environmental stresses affecting domestic animal production, particularly commercial poultry, subsequently causing severe yearly economic losses. Heat stress, a major source of oxidative stress, stimulates mitochondrial oxidative stress and cell dysfunction, leading to cell damage and apoptosis. Cell survival under stress conditions needs urgent response mechanisms and the consequent effective reinitiation of cell functions following stress mitigation. Exposure of cells to heat-stress conditions induces molecules that are ready for mediating cell death and survival signals, and for supporting the cell's tolerance and/or recovery from damage. Heat-shock proteins (HSPs) confer cell protection against heat stress via different mechanisms, including developing thermotolerance, modulating apoptotic and antiapoptotic signaling pathways, and regulating cellular redox conditions. These functions mainly depend on the capacity of HSPs to work as molecular chaperones and to inhibit the aggregation of non-native and misfolded proteins. This review sheds light on the key factors in heat-shock responses for protection against cell damage induced by heat stress in chicken.

Differential expression of small heat shock proteins in the brain of broiler embryo; the effects of embryonic thermal manipulation

Broilers are more vulnerable to high temperatures than mammals due to the feather cover, lack of sweat glands, fast growth and intensive breeding in commercial systems. Thermal stresses affect the function of various organs and change the expression profiles of hundreds of genes in the different tissues of broilers. Thermal manipulation (TM) during embryogenesis can increase heat tolerance in growing broilers. Small heat shock proteins (SHSPs) are a group of HSPs which participate in many cellular functions like response to different stressors. However, their role in the thermotolerance has not been fully elucidated. Ninety fertilized eggs were randomly divided into three groups (30 eggs/group; 10 eggs/replicate). Normal control (NC) eggs were incubated at 37.5 °C throughout the incubation period whereas heat stress (HS) and cold stress (CS) groups were kept at 41 °C and 33 °C from 15 to 17th day of incubation for 3 h each day, respectively. On day 20, samples from the cerebrums were harvested for histopathology and mRNA expression analyses of HSPB1, HSPB5, HSPB8, and HSPB9. There were no significant differences in survivability, defected embryos, hatchability, and body weight among treatments. TM had no major deleterious effects on the cerebral tissue except for mild degeneration in the HS group. HSPB1, HSPB5, HSPB8, and HSPB9 were expressed in the presence and absence of TM. All SHSP genes tested were downregulated in response to TM except for HSPB9 which was upregulated in the HS group. The highest change in gene expression due to TM observed for HSPB1. This study presents a broader understanding of mechanisms underlying response to TM in broilers. The results suggest that HSPB1, HSPB5, HSPB8, and HSPB9 are involved in thermotolerance in broilers and SHSPs could be involved in the gene expression profiling of TM. It may propose the use of nutritional supplements in the poultry industry to modulate SHSPs.

Heat shock protein B1 expression is associated with age at sexual maturity in Rhode Island Red and Punjab Red layers under heat stress

Heat shock proteins (Hsp) aid in protein folding and also to combat stress in all cellular organisms. HspB1 is a member of the small HSP family that has a significant role in thermo-tolerance. In this study, we aimed to determine the relationship (if any) between age at sexual maturity of layer poultry (Rhode Island Red and Punjab Red) and HspB1 expression both at mRNA and protein levels under heat stress. The mRNA expression of hspB1 was checked by real-time PCR. Delay in sexual maturity of the birds was found to be directly associated with the hspB1 mRNA expression in both the bird varieties under heat stress. No significant regression (association) of hspB1 mRNA expression with age at sexual maturity was observed in case of control, non-heat stressed birds. The serum levels of HspB1 were measured by indirect ELISA, using recombinant HspB1 that was expressed using pET-32b(+) vector in BL21(DE3) cells. Serum HspB1 concentration increased significantly (p ≤ 0.001) in heat-stressed birds as compared with control ones. A significant association was found between the increase in serum HspB1 concentration and delay in sexual maturity of all the birds under heat stress while no such association was found in control birds. In conclusion, HspB1 mRNA and protein expression were found to be associated with age at sexual maturity in Punjab Red and RIR layers under heat stress.

Heat-Shock Proteins Gene Expression in Peripheral Blood Mononuclear Cells as an Indicator of Heat Stress in Beef Calves

Simple Summary

This study explores the effects of heat stress on the expression of various heat-shock protein (HSP) genes in bovine peripheral blood mononuclear cells (PBMCs) and cell viability as an indicator of stress in beef calves. We found that heat stress inhibits cell proliferation and increases the expression of HSPs in an in vitro model. In addition, HSPs were found to regulate the physiological mechanisms of adaptation to heat stress in an in vivo model. The results showed that HSPs expression in PBMCs can be used as an indicator of heat stress (HS) in beef calves.

Abstract

This study was conducted to investigate the effect of HS on HSPs gene expression in bovine PBMCs of beef calves in in vitro and in vivo models. In the in vitro experiment, blood samples were collected from the jugular vein of five beef calves (age: 174.2 ± 5.20 days, BW: 145.2 ± 5.21 kg). In the in vivo experiment, sixteen Korean native male beef calves (age: 169.6 ± 4.60 days, BW: 136.9 ± 6.23 kg) were exposed to ambient temperature for seven days (22 to 24 °C, relative humidity 60%; temperature–humidity index (THI) = 68 to 70) and subsequently to the temperature and humidity corresponding to the target THI level for 21 days (HS). For PBMC isolation, blood samples were collected every three days. In the in vitro model, the cell viability was significantly decreased in HS groups compared with the control group (p = 0.015). The expression of HSP70 (p = 0.022), HSP90 (p = 0.003) and HSPB1 (p = 0.026) genes was increased in the HS group in in vitro model. In the in vivo experiment, the HSP70 gene expression was increased after sudden exposure to HS conditions (severe THI levels; THI = 88 to 90), whereas HSP90 and HSPB1 showed no differences among the THI groups (p > 0.05). However, in the severe THI group, the HSP70 gene expression returned to normal range after six days of continuous HS. In conclusion, the HSP70 gene plays a pivotal role in protecting cells from damage and is sensitive to HS in immune cells compared with other HSP genes in in vitro and in vivo models. In addition, the in vivo models suggest that calves exhibit active physiological mechanisms of adaptation to HS after six days of continuous exposure by regulating the HSP70 gene expression.

MiR-499 inhibited hypoxia/reoxygenation induced cardiomyocytes injury by targeting SOX6

Objective

MiR-499 has been reported to be expressed only in cardiomyocytes, and its expression would increase after acute myocardial infarction (AMI). miR-499 plays a role in the process of cardiomyocytes injury induced by hypoxia/reoxygenation (H/R), however, it still remains unclear.

Results

Hypoxia inhibited miR-499-5p expression and H/R induced apoptosis. SOX6 was a target gene of miR-499-5p, and high expression of miR-499-5p inhibited the expression of SOX6. MiR-499-5p reduced H9c2 cells injury by inhibiting the expression of SOX6, overexpression of which could reverse the effect of miR-499-5p on H9c2 cells. MiR-499-5p inhibited the levels of LDH and MDA, while overexpression of miR-499-5p inhibited H/R-induced cell apoptosis. MiR-499-5p could up-regulate the level of Bcl-2 and down-regulate the expression levels of Bax and caspase-3. However, SOX6 partially reversed these effects of miR-499-5p.

Conclusion

We proved that miR-499-5p inhibited H/R-induced cardiomyocytes injury by targeting SOX6. Our results suggested that miR-499-5p/SOX6 pathway may present a potential therapeutic target for the treatment of AMI.

Effects of probiotic (Bacillus subtilis) supplementation on meat quality characteristics of breast muscle from broilers exposed to chronic heat stress

The aim of this study was to determine the impact of probiotic feeding and chronic heat stress on meat quality, total lipid and phospholipid contents, lipid oxidation, antioxidant capacity, and heat shock protein abundance of broiler breast muscle. A total of 240 male broilers (5 birds per pen) were subjected to 4 treatments consisting of a 2 × 2 factorial design. Broilers were kept at 21-32-21°C for 10 h daily (heat stress, HS) or 21°C (thermoneutral condition) and fed a regular diet or the diet mixed with probiotic (250 ppm of Sporulin containing 3 strains of Bacillus subtilis). A total of 48 broilers (12 birds/treatment) were harvested at 46 d. Neither HS nor probiotic had substantial impacts on water-holding capacity, shear force, and color characteristics. HS induced lipid oxidation as increased 2-thiobarbituric acid reactive substances (TBARS), in which probiotic feeding decreased TBARS value (P = 0.002) and phospholipid contents (P = 0.0033) in breast muscle of HS broilers. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was increased with HS (P < 0.0001), but no significant impact of probiotic supplementation was found. Neither probiotic nor HS affected catalase activity, but superoxide dismutase and glutathione peroxidase activities were lower in HS broilers compared to thermoneutral controls (P < 0.0001) and in probiotics-fed broilers (P < 0.0001) compared to their counterparts. In addition, a significant interaction between probiotic and HS was found at glutathione peroxidase activities, in which breast muscle of broilers fed probiotic at thermoneutral condition showed the highest activity (P < 0.05). Regarding heat shock protein (HSP) determination, HS slightly increased the levels of both HSP70 (P = 0.08) and HSP27 (P = 0.05), but no significant impacts of probiotic supplementation were found. Our results indicate that probiotic feeding could improve breast muscle weight without adverse impacts on meat quality attributes, as well as alleviate oxidative deterioration of breast muscle of broilers undergoing heat stress.

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.

Hsp70 expression induced by Co-Enzyme Q10 protected chicken myocardial cells from damage and apoptosis under in vitro heat stress

The aim of this study was to investigate whether induction of Hsp70 expression by co-enzyme Q10 (Q10) treatment protects chicken primary myocardial cells (CPMCs) from damage and apoptosis in response to heat stress for 5 hours. Analysis of the expression and distribution of Hsp70 and the levels of the damage-related enzymes creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH), as well as pathological analysis showed that co-enzyme Q10 alleviated the damage caused to CPMCs during heat stress. Further, analysis of cell apoptosis and the expression of cleaved caspase-3 indicated that co-enzyme Q10 did have an anti-apoptotic role during heat stress. Western blot analysis showed that pretreatment with co-enzyme Q10 led to a significant increase in the expression of Hsp70 during heat stress. Immunostaining assays confirmed the results of western blot analysis and also showed that co-enzyme Q10 could accelerate the translocation of Hsp70 into the nucleus during heat stress, but this was not observed in the group that was treated with only co-enzyme Q10. These findings seem to indicate that co-enzyme Q10 protected CPMCs from heat stress via the induction of Hsp70. To investigate this, 200 μM quercetin, an Hsp70 inhibitor, was used to inhibit the expression of Hsp70 2 h before heat stress. Quercetin pre-treatment was observed to suppress the expression of Hsp70 as well the protective function of co-enzyme Q10 at 5 h of heat stress. This finding confirms that Q10 brought about its effects via Hsp70 expression, but the mechanism underlying this needs further investigation.

Maduramicin induces apoptosis in chicken myocardial cells via intrinsic and extrinsic pathways

Maduramicin is one of the most extensively used anticoccidial drugs for the treatment of Eimeria spp. infections. However, overdosage, misuse and drug interactions have resulted in the development of ionophore toxic syndrome. Heart and skeletal muscles have been identified as the main target organs of toxicity. In the present study, primary chicken myocardial cells were isolated to investigate the toxicity and underlying mechanisms of maduramicin. Our results showed that maduramicin causes morphological changes and a decrease in the viability of chicken myocardial cells. Annexin V-FITC/PI and 4',6-diamidino-2-phenylindole (DAPI) staining showed a significant increase in the number of apoptotic cells. Furthermore, caspases-3/8/9 were activated at the gene and protein levels and this was accompanied by the upregulation of apoptosis-related genes, including bcl-2, bax, and cytochrome C. Treatment with the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp (O-Me) fluoromethyl ketone (z-VAD-fmk) ameliorated the apoptosis and cytotoxicity. Furthermore, intracellular Ca²⁺ and reactive oxygen species (ROS) were elevated, whereas mitochondrial membrane potential (MMP) and intracellular glutathione (GSH) decreased with exposure to maduramicin. The antioxidant N-acetyl-cysteine (NAC) had no significant effect on maduramicin-induced cytotoxicity and apoptosis. Taken together, our findings demonstrate that maduramicin is cytotoxic to primary chicken myocardial cells via caspase dependent and independent apoptotic pathways.

Co-enzyme Q10 and acetyl salicylic acid enhance Hsp70 expression in primary chicken myocardial cells to protect the cells during heat stress

We investigated the effects of co-enzyme Q10 (Q10) and acetyl salicylic acid (ASA) on expression of Hsp70 in the protection of primary chicken myocardial cells during heat stress. Western blot analysis showed that Q10 and ASA accelerated the induction of Hsp70 when chicken myocardial cells were exposed to hyperthermia. In the absence of heat stress, however, neither Q10 nor ASA are able to upregulate Hsp70 expression. Analysis of enzymes that respond to cellular damage and pathological examination revealed that ectopic expression of ASA and Q10 alleviate cellular damage during heat stress. Quantification of heat shock factors (HSF) indicated that treatment of ASA increased the expression of HSF-1 and HSF-3 during heat stress. Treatment with Q10 resulted in the elevation of HSF-1 expression. Expression of HSF-2 and HSF-4 was not affected by ASA or Q10. Subcellular distribution analysis of HSF-1 and HSF-3 showed that in response to heat stress ASA promoted nuclear translocation of HSF-1 and HSF-3, while Q10 promoted only HSF-1 nuclear translocation. Chromatin immunoprecipitation (ChIP) analysis indicated that HSF-1 occupies the Hsp70 promoter in chicken primary myocardial cells during heat stress and under normal conditions, while HSF-3 occupies the Hsp70 promoter only during heat stress. Real-time PCR analysis revealed that ASA induces HSF-1 and HSF-3 binding to Hsp70 HSE, while Q10 only induces HSF1 binding to Hsp70 HSE, in agreement with the impact of HSF1 and HSF3 silencing on Hsp70 expression. These data demonstrate that ASA and Q10 both induce the expression of Hsp70 to protect chicken primary myocardial cells during heat stress, but through distinct pathways.

Aspirin upregulates αB-Crystallin to protect the myocardium against heat stress in broiler chickens

We established in vivo and in vitro models to investigate the role of αB-Crystallin (CryAB) and assess the ability of aspirin (ASA) to protect the myocardium during prolonged heat stress. Thirty-day-old chickens were divided into three groups (n = 90): heat stress (HS, 40±1 °C); ASA(−)HS(+), 1 mg/kg ASA orally 2 h before heat stress; and ASA(+)HS(−), pretreated with aspirin, no heat stress (25 °C). Hearts were excised after 0, 1, 2, 3, 5, 7, 10, 15 and 24 h. Heat stress increased body temperature, though the ASA(−)HS(+) group had significantly higher temperatures than the ASA(+)HS(+) group at all time points. Compared to ASA(+)HS(+), the ASA(−)HS(+) group displayed increased sensitivity to heat stress. Pathological analysis revealed the ASA (+)HS(+) myocardium showed less severe changes (narrowed, chaotic fibers; fewer necrotic cells) than the ASA(−)HS(+) group (bleeding and extensive cell death). In vitro, ASA-pretreatment significantly increased primary chicken myocardial cell survival during heat stress. ELISAs indicated ASA induced CryAB in vivo to protect against heat stress-induced myocardial damage, but ASA did not induce CryAB in primary chicken myocardial cells. The mechanisms by which ASA induces the expression of CryAB in vivo and protects the myocardium during heat stress merit further research.

Aspirin-induced heat stress resistance in chicken myocardial cells can be suppressed by BAPTA-AM in vitro

Our recent studies have displayed the protective functions of aspirin against heat stress (HS) in chicken myocardial cells, and it may be associated with heat shock proteins (HSPs). In this study, we further investigated the potential role of HSPs in the aspirin-induced heat stress resistance. Four of the most important HSPs including HspB1 (Hsp27), Hsp60, Hsp70, and Hsp90 were induced by aspirin pretreatment and were suppressed by BAPTA-AM. When HSPs were induced by aspirin, much slighter HS injury was detected. But more serious damages were observed when HSPs were suppressed by BAPTA-AM than those cells exposed to HS without BAPTA-AM, even the myocardial cells have been treated with aspirin in prior. Comparing to other HSPs, HspB1 presented the largest increase after aspirin treatments, 86-fold higher than the baseline (the level before HS). These findings suggested that multiple HSPs participated in aspirin's anti-heat stress function but HspB1 may contribute the most. Interestingly, during the experiments, we also found that apoptosis rate as well as the oxidative stress indicators (T-SOD and MDA) was not consistently responding to heat stress injury as expected. By selecting from a series of candidates, myocardial cell damage-related enzymes (CK-MB and LDH), cytopathological tests, and necrosis rate (measured by flow cytometry assays) are believed to be reliable indicators to evaluate heat stress injury in chicken's myocardial cells and they will be used in our further investigations.