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

Identification of key Genes and Pathways Associated With Thermal Stress in Peripheral Blood Mononuclear Cells of Holstein Dairy Cattle

“…The expression of HSPA1A was related to the levels of blood hormones (Hu et al, 2019;Abbas et al, 2020a). Consistent with our present study, 25 • C was already adopted as the mild cold shock treatment temperature to study cold stress response in WI26 cells (Neutelings et al, 2013), whereas 42 • C was adopted to simulate heat stress conditions for Korean native male beef calves (Kim et al, 2020), riverine buffaloes (Bubalus bubalis), exotic cattle (Bos taurus), and native cattle (Bos indicus) of India (Kishore et al, 2014). Hence, we selected 25 and 42 • C to construct a feasible acute thermal stress cell model.…”

“…The impact of thermal stress on cows is difficult to assess due to the complexity of animal metabolic and physiological systems. Peripheral blood mononuclear cells (PBMCs) are a common cell model that can be easily isolated and cultured to reflect the overall physiological condition of the cattle ( Lacetera et al, 2006 ; Kishore et al, 2014 ; Kim et al, 2020 ). Therefore, the present study is designed to identify key genes and pathways that responded to acute thermal stress in Holstein dairy cattle at the PBMCs and individual levels.…”

Effects of Different Protein Levels on Growth Performance and Stress Parameters in Beef Calves Under Heat Stress

“…The HSP genes result in the expression of proteins with chaperone roles that act in protecting cells from HS and in the removal of damaged proteins [53,54]. In the current study, the HSP70 gene expression in PBMCs and hair follicles was increased in HS groups.…”

Effects of Different Protein Levels on Growth Performance and Stress Parameters in Beef Calves Under Heat Stress

“…The HSP genes result in the expression of proteins with chaperone roles that act in protecting cells from HS and removing damaged proteins 21,54 . In the current study, the HSP70 gene expression in PBMCs and hair follicles was increased in HS groups.…”

“…The whole blood was diluted 1:1 with 1 × PBS (Hyclone, Laboratories, INC., Logan, UT, USA) and layered gently over Histopaque-1077 (Sigma-Aldrich Inc., St. Louis, MO, USA). All the PBMC isolation steps were performed at room temperature, following the manufacturer's instructions 21 .…”