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

Ling Kang,Yachun Wang,Zaheer Abbas,Qing Xu,Lirong Hu,Yumei Chen,Hao Fang,Xiao Tan

doi:10.3389/fgene.2021.662080

Ling Kang, Yachun Wang + Show 6 more

Open Access

https://doi.org/10.3389/fgene.2021.662080

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Abstract

The objectives of the present study were to identify key genes and biological pathways associated with thermal stress in Chinese Holstein dairy cattle. Hence, we constructed a cell-model, applied various molecular biology experimental techniques and bioinformatics analysis. A total of 55 candidate genes were screened from published literature and the IPA database to examine its regulation under cold (25°C) or heat (42°C) stress in PBMCs. We identified 29 (3 up-regulated and 26 down-regulated) and 41 (15 up-regulated and 26 down-regulated) significantly differentially expressed genes (DEGs) (fold change ≥ 1.2-fold and P < 0.05) after cold and heat stress treatments, respectively. Furthermore, bioinformatics analyses confirmed that major biological processes and pathways associated with thermal stress include protein folding and refolding, protein phosphorylation, transcription factor binding, immune effector process, negative regulation of cell proliferation, autophagy, apoptosis, protein processing in endoplasmic reticulum, estrogen signaling pathway, pathways related to cancer, PI3K- Akt signaling pathway, and MAPK signaling pathway. Based on validation at the cellular and individual levels, the mRNA expression of the HIF1A gene showed upregulation during cold stress and the EIF2A, HSPA1A, HSP90AA1, and HSF1 genes showed downregulation after heat exposure. The RT-qPCR and western blot results revealed that the HIF1A after cold stress and the EIF2A, HSPA1A, HSP90AA1, and HSF1 after heat stress had consistent trend changes at the cellular transcription and translation levels, suggesting as key genes associated with thermal stress response in Holstein dairy cattle. The cellular model established in this study with PBMCs provides a suitable platform to improve our understanding of thermal stress in dairy cattle. Moreover, this study provides an opportunity to develop simultaneously both high-yielding and thermotolerant Chinese Holstein cattle through marker-assisted selection.

Highlights

Extreme climatic events are the main threats to the survivability and maintenance of the dairy industry around the world (Das et al, 2016)
To select the optimum cold and heat stress treatment temperatures, we comprehensively considered the cell viability and the expression of inducible HSPA1A gene in Peripheral blood mononuclear cells (PBMCs) after treated at different temperatures viz. 10, 25, 32, 37, 39, and 42◦C for 1 h
Based on the results and criteria that we described in details above, a total of 7 genes were recognized as important genes that respond to thermal stress, viz. DNAJB1, EIF2A, hypoxia-inducible factor-1A (HIF1A), HSPA1A, HSP90AA1, HSPD1, and Heat shock factor 1 (HSF1)

Summary

Introduction

Extreme climatic events are the main threats to the survivability and maintenance of the dairy industry around the world (Das et al, 2016). The temperature at which cows show optimum production ranges from –5 to 25◦C, once exceeds this range Holstein dairy cattle show signs of cold or heat stress (Berman et al, 1985; Bernabucci et al, 2010). The most economical and effective measure to deal with thermal stress is the selective breeding of both highyielding and thermotolerant breeds (Renaudeau et al, 2012). This highlights the importance of elucidating the biological mechanism and the genetic factors of thermal stress response in dairy cattle

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