Expression dynamics of HSP90 and nitric oxide synthase (NOS) isoforms during heat stress acclimation in Tharparkar cattle

Androgen receptor gene deficiency results in the reduction of steroidogenic potential in porcine luteal cells

Luteal steroidogenesis is critical to implantation and pregnancy maintenance in mammals. The role of androgen receptors (AR) in the progesterone (P4) producing luteal cells of porcine corpus luteum (CL) remains unexplored. The aim of the present study was to establish AR gene knock out (KO) porcine luteal cell culture system model by CRISPR/Cas9 genome editing technology and to study the downstream effects of AR gene deficiency on steroidogenic potential and viability of luteal cells. For this purpose, genomic cleavage detection assay, microscopy, RT-qPCR, ELISA, annexin, MTT, and viability assay complemented by bioinformatics analysis were employed. There was significant downregulation (p < 0.05) in the relative mRNA expression of steroidogenic marker genes STAR, CYP11A1, HSD3B1 in AR KO luteal cells as compared to the control group, which was further validated by the significant (p < 0.05) decrease in the P4 production. Significant decrease (p < 0.05) in relative viability on third passage were also observed. The relative mRNA expression of hypoxia related gene HIF1A was significantly (p < 0.05) downregulated in AR KO luteal cells. Protein-protein interaction analysis mapped AR to signaling pathways associated with luteal cell functionality. These findings suggests that AR gene functionality is critical to luteal cell steroidogenesis in porcine.

Heat stress adaptation in cows - Physiological responses and underlying molecular mechanisms

Heat stress is a key abiotic stressor for dairy production in the tropics which is further compounded by the ongoing climate change. Heat stress not only adversely impacts the production and welfare of dairy cows but severely impacts the economics of dairying due to production losses and increased cost of rearing. Over the years, selection has ensured development of high producing breeds, however, the thermotolerance ability of animals has been largely overlooked. In the past decade, the ill effects of climate change have made it pertinent to rethink the selection strategies to opt for climate resilient breeds, to ensure optimum production and reproduction. This has led to renewed interest in evaluation of the impacts of heat stress on cows and the underlying mechanisms that results in their acclimatization and adaptation to varied thermal ambience. The understanding of heat stress and associated responses at various level of animal is crucial to device amelioration strategies to secure optimum production and welfare of cows. With this review, an effort has been made to provide an overview on temperature humidity index as an important indicator of heat stress, general effect of heat stress in dairy cows, and impact of heat stress and subsequent response at physiological, haematological, molecular and genetic level of dairy cows.

Invited review: From heat stress to disease-Immune response and candidate genes involved in cattle thermotolerance

Heat stress implies unfavorable effects on primary and functional traits in dairy cattle and, in consequence, on the profitability of the whole production system. The increasing number of days with extreme hot temperatures suggests that it is imperative to detect the heat stress status of animals based on adequate measures. However, confirming the heat stress status of an individual is still challenging, and, in consequence, the identification of novel heat stress biomarkers, including molecular biomarkers, remains a very relevant issue. Currently, it is known that heat stress seems to have unfavorable effects on immune system mechanisms, but this information is of limited use in the context of heat stress phenotyping. In addition, there is a lack of knowledge addressing the molecular mechanisms linking the relevant genes to the observed phenotype. In this review, we explored the potential molecular mechanisms explaining how heat stress affects the immune system and, therefore, increases the occurrence of immune-related diseases in cattle. In this regard, 2 relatively opposite hypotheses are under focus: the immunosuppressive action of cortisol, and the proinflammatory effect of heat stress. In both hypotheses, the modulation of the immune response during heat stress is highlighted. Moreover, it is possible to link candidate genes to these potential mechanisms. In this context, immune markers are very valuable indicators for the detection of heat stress in dairy cattle, broadening the portfolio of potential biomarkers for heat stress.

Expression profiling of heat shock protein genes in whole blood of Romosinuano cattle breed

Background and Aim: Heat shock proteins are highly conserved proteins that work as molecular chaperones expressed in response to thermal stress. This study aimed to determine the expression profile of genes related to the heat stress response in whole blood obtained from the Romosinuano creole breed. Materials and Methods: Real-time polymerase chain reaction was performed to analyze the transcript of hsp90, hsp70, hsp60, and hsf1 in the whole blood of Romosinuano under different temperature-humidity indices (THIs). Results: The expression levels of the hsp70 and hsf1 genes at the high-THI level were higher (p = 0.0011 and p = 0.0003, respectively) than those at the low-THI level. In addition, no differences in the expression levels of the hsp60 and hsP90 genes were detected between the two THIs. Conclusion: The overexpression of hsf1 and hsp70 genes play an important role in protecting cells from damage induced by heat stress. Keywords: climate change, external environment, heat shock proteins, heat stress, mRNA, temperature-humidity index.

Expression profiling of heat shock protein genes in whole blood of Romosinuano cattle breed

Background and Aim

Heat shock proteins are highly conserved proteins that work as molecular chaperones expressed in response to thermal stress. This study aimed to determine the expression profile of genes related to the heat stress response in whole blood obtained from the Romosinuano creole breed.

Materials and Methods

Real-time polymerase chain reaction was performed to analyze the transcript of hsp90, hsp70, hsp60, and hsf1 in the whole blood of Romosinuano under different temperature-humidity indices (THIs).

Results

The expression levels of the hsp70 and hsf1 genes at the high-THI level were higher (p = 0.0011 and p = 0.0003, respectively) than those at the low-THI level. In addition, no differences in the expression levels of the hsp60 and hsP90 genes were detected between the two THIs.

Conclusion

The overexpression of hsf1 and hsp70 genes play an important role in protecting cells from damage induced by heat stress.

Monoammonium glycyrrhizinate improves antioxidant capacity of calf intestinal epithelial cells exposed to heat stress in vitro

Dairy calves are highly susceptible to the negative effects of heat stress, which can cause organ hypoxia after blood redistribution, damage the intestinal barrier, and trigger intestinal oxidative stress. This study aimed to investigate the antioxidant effects of monoammonium glycyrrhizinate (MAG) on calf small intestinal epithelial cells under heat stress in vitro. Small intestinal epithelial cells were isolated from a 1-d-old healthy calf and purified by differential enzymatic detachment. The purified cells were divided into seven groups. The control group was cultured with DMEM/F-12 at 37 °C for 6 h, and the treatment groups were cultured with 0, 0.1, 0.25, 0.5, 1, or 5 μg/mL MAG at 42 °C for 6 h. Heat stress causes oxidative damage to cells. Adding MAG to the medium can significantly improve cell activity and reduce cellular oxidative stress. MAG significantly increased the total antioxidant capacity and superoxide dismutase activity caused by heat stress, and significantly decreased malondialdehyde and nitric oxide levels. The MAG treatment also reduced lactate dehydrogenase release, increased mitochondrial membrane potential, and decreased apoptosis under heat stress. MAG also upregulated the expression of the antioxidant-related genes, Nrf2 and GSTT1, in heat-stressed intestinal epithelial cells and significantly downregulated the expression of the heat shock response-related proteins, MAPK, HSP70, HSP90, and HSP27. From the above results, we conclude that 0.25 μg/mL MAG improves the capability of the antioxidant system in small intestinal epithelial cells to eliminate reactive oxygen species by activating antioxidant pathways, improving the oxidant/antioxidant balance, lowering excessive heat shock responses, and reducing intestinal oxidative stress.

Identification of Reference Genes for Expression Studies in the Whole-Blood from Three Cattle Breeds under Two States of Livestock Weather Safety

Simple Summary

Reductions in the fertility, body weight, and growth rate of cattle across the world are associated with the global warming phenomenon. Developing optimal management strategies is an important aspect of breeding programs for different breeds. Blood tissue undergoes dramatic physiological and metabolic changes during heat stress conditions, which involves the expression and regulation of a great number of genes across species. Real-time quantitative PCR (qPCR) is a method for the rapid and reliable quantification of mRNA transcription. Reference genes are used to normalize mRNA levels between different samples. Thus, the selection of high-quality reference genes is necessary for the interpretation of data generated by real-time PCR.

Abstract

Real-time PCR is widely used to study the relative abundance of mRNA due to its specificity, sensitivity, and repeatability quantification. However, relative quantification requires a reference gene, which should be stable in its expression, showing lower variation by experimental conditions or tissues. The aim of this study was to evaluate the stability of the expression of five commonly used reference genes (actb, ywhaz, b2m, sdha, and 18s rRNA) at different physiological stages (alert and emergency) in three different cattle breeds. In this study, five genes (actb, ywhaz, b2m, sdha, and 18s rRNA) were selected as candidate reference genes for expression studies in the whole blood from three cattle breeds (Romosinuano, Gyr, and Brahman) under heat stress conditions. The transcription stability of the candidate reference genes was evaluated using geNorm and NormFinder. The results showed that actb, 18SrRNA, and b2m expression were the most stable reference genes for whole blood of Gyr and Brahman breeds under two states of livestock weather safety (alert and emergency). Meanwhile, actb, b2m, and ywhaz were the most stable reference genes for the Romosinuano breed.

Differential expression of miRNAs and related mRNAs during heat stress in buffalo heifers

The present experiment was aimed to study differential expression of miRNAs and related mRNAs during heat stress (HS) in buffalo heifers. Twelve Murrah buffalo heifers aged between 1.5 and 2.0 years, weighting between 250 and 300 Kg were randomly assigned into two equal groups. The animals were kept in the psychrometric chamber under Thermo-neutral (TN; THI = 72) and HS (THI = 87-90) conditions for 6 h every day between 1000 and 1600 h for 21 days. The blood sampling was done at 1500 h on 15th day of the experiment and physiological parameters viz. pulse rate (PR), respiratory rate (RR) and rectal temperature (RT) were recorded at 1500 h on day -5, -3, -1, 0, +1, +3, +5 with respect to blood sampling. PBMCs were used for extraction of miRNAs and total RNA; and first strand cDNA was synthesized. qPCR was performed for relative gene expression studies. Physiological, hematological (erythrocytic indices), biochemical (triglycerides, urea, ALT, AST, LDH), redox (SOD, ROS) and endocrine parameters (T₄) altered significantly (P < 0.05) during HS as compared to TN. Out of eight targeted miRNAs only four were expressed in buffalo heifers. The relative expression of bta-mir-142, bta-mir-1248 and bta-mir-2332 was significantly (P < 0.05) up-regulated whereas expression of bta-mir-2478 was significantly (P < 0.05) down-regulated during HS as compared to TN. The relative expression of the predicted target genes i.e. HSF1, HSP60, HSP70, HSPA8 and HSP90 were significantly (P < 0.05) up-regulated whereas HSF4 expression was significantly (P < 0.05) down-regulated during HS as compared to TN. It can be concluded that a THI of 87-90 could lead to a moderate HS in buffalo heifers. Differential expression studies of miRNAs and related mRNAs in present study deciphers the role of miRNAs in the heat tolerance in buffalo heifers.

Significance of molecular chaperones and micro RNAs in acquisition of thermo-tolerance in dairy cattle

Ambient temperature is considered as the major abiotic factor which regulates body physiological mechanisms of all living creatures across the globe. Variation in ambient temperature which emulates thermoneutral zone culminates in heat stress. Heat stress has been emerged as major ultimatum to livestock's growth, development, production and reproduction across the world. Livestock's responds to the heat stress via different mechanisms such as behavioral, physiological, biochemical, endocrine and molecular mechanisms. Amongst the aforementioned mechanisms, molecular mechanism plays crucial role to achieve thermo-tolerance via expression of highly conserved family of proteins known as heat shock proteins (HSPs) across livestock species. HSPs serve as molecular chaperones to ameliorate the menace of heat stress in domestic species. In addition, microRNAs are small non-coding RNA which down regulates post-transcriptional gene expression by targeting various HSPs to regulate the thermoregulatory responses in livestock species. Despite of thermal adaptation mechanisms, heat stress breaches animal body homeostasis thereby depresses their production and productivity. Therefore, veterinary researches have been targeting to explore different repertoire of HSPs and microRNAs expression to counteract the rigors of heat stress thereby confer thermo-tolerance in livestock species. The present review highlights the significance of molecular chaperones and microRNAs in the acquisition of thermo-tolerance in dairy cattle.

Alpha lipoic acid supplementation ameliorates the wrath of simulated tropical heat and humidity stress in male Murrah buffaloes

A supplement which ameliorates temperature-humidity menace in food producing livestock is a prerequisite to develop climate smart agricultural packages. A study was conducted to investigate the heat stress ameliorative efficacy of alpha lipoic acid (ALA) in male Murrah water buffaloes (Bubalus bubalis). Eighteen animals (293.61 ± 4.66Kg Bwt) were randomly allocated into three groups (n = 6); NHSC (non-heat-stressed control), HS (heat-stressed) and HSLA (heat-stressed-supplemented with ALA@32 mg/kg Bwt orally) based on the temperature humidity index (THI) and ALA supplementation. HS and HSLA were exposed to simulated heat challenge in a climatically controlled chamber (40 °C) for 21 consecutive days, 6 h daily. Physiological responses viz. Respiration rate (RR), Pulse rate (PR) and Rectal temperature (RT) were recorded daily before and after heat exposure. Blood samples were collected at the end of heat exposure on days 1, 6, 11, 16, and 21 and on day 28 (7th day post exposure which is considered as recovery) for peripheral blood mononuclear cells (PBMCs) separation, followed by RNA and Protein extraction for Real time quantitative PCR and Western blot analysis respectively, of heat shock proteins (HSPs). Two-way repeated measure ANOVA was performed between groups at different experimental periods. RR (post exposure) in HS and HSLA was significantly higher (P < 0.05) than NHSC from day 1 onwards but HSLA varied significantly from the HS 8th day onwards. Post exposure RT and PR in both HS and HSLA varied (P < 0.05) from NHSC throughout the study; but between HS and HSLA, RT significantly varied on initial 2 days and last 6 days (from days 16 to 21). HSP70 mRNA expression significantly up regulated in high THI groups with respect to the low THI group throughout the experimental period. During chronic stress (days 16 and 21) HSP70 significantly (P < 0.05) increased in HS but not in HSLA (P > 0.05) with respect to NHSC. ALA supplementation up-regulates and sustains (P < 0.05) the expression of HSP90 in HSLA in comparison to the HS and NHSC. HSP105 expression was significantly up-regulated (P < 0.05) in HS on days 16 and 21 (during long-term exposure) but only on day 21 (P < 0.05) in HSLA. HSP70, HSP90, and HSP105 protein expression dynamics were akin to the mRNA transcript data between the study groups. In conclusion, supplementing ALA ameliorates the deleterious effect of heat stress as reflected by improved physiological and cellular responses. ALA supplementation improved cellular antioxidant status and sustained otherwise easily decaying heat shock responses which concertedly hasten the baton change from a limited window of thermo tolerance to long run acclimatization.

Meta-inflammation and cardiometabolic disease in obesity: Can heat therapy help?

Obesity and associated metabolic dysfunction have reached epidemic proportions worldwide. The current theory linking metabolic disease and obesity involves ischemic adipose tissue initiating an inflammatory cascade that results in systemic insulin resistance and may eventually lead to type II diabetes mellitus. Diabetes and associated metabolic dysfunction increase the risk of developing cardiovascular disease and fatal cardiovascular events. By targeting key steps in this process, ischemia and inflammation, this cascade may be prevented or reversed and thus metabolic and cardiovascular health may be preserved in obesity. Regular heat exposure (termed ‘heat therapy’) offers potential to improve cardiometabolic health in obese individuals through a variety of mechanisms that include but are not limited to heat shock proteins, hypoxia-inducible factor 1α, and hemodynamic effects. The purpose of this review is to highlight the cardiometabolic decline in obese individuals stemming from adipose tissue dysfunction, and examine the ways in which heat therapy and associated cellular and systemic adaptations can intersect with this decline in function to improve or restore cardiovascular and metabolic health.