Molecular characterization of mudskipper (Boleophthalmus pectinirostris) hypoxia-inducible factor-1α (HIF-1α) and analysis of its function in monocytes/macrophages

Abstract

Hypoxia-inducible factor-1α (HIF-1α) plays a critical role in immune and inflammatory responses and is important in controlling a variety of processes in monocytes and macrophages. However, very little information is available about the functions of HIF-1α in fish monocytes/macrophages (MO/MФ). In this study, the cDNA sequence of the mudskipper (Boleophthalmus pectinirostris) HIF-1α gene (BpHIF-1α) was determined. Sequence comparison and phylogenetic tree analysis showed that BpHIF-1α is clustered in the fish HIF-1α tree. Constitutive expression of BpHIF-1α mRNA was detected by real-time quantitative PCR in all tested tissues, and the expression was found to be dramatically increased in the skin, liver, spleen, and kidney after Edwardsiella tarda infection. In addition, hypoxia and infection induced the expression of the BpHIF-1α transcript and protein in MO/MФ, respectively. Hypoxia caused an increase in phagocytic and bactericidal capacity of mudskipper MO/MФ in a BpHIF-1α-dependent manner. BpHIF-1α induced an anti-inflammatory status in MO/MФ upon E. tarda infection and hypoxia. Therefore, BpHIF-1α may play a predominant role in the modulation of mudskipper MO/MФ function in the innate immune system.

Effect of secondary attack by Aeromonas hydrophila on the expression level of hif genes in common carp (Cyprinus carpio)

“…In this study, most hif genes were down-regulated after A. hydrophila infection in a common carp population. Although the down-regulation of hif1 is rarely observed after bacterial infection, we have found similar phenomena in other studies, such as when Boleophthalmus pectinirostris were infected with Edwardsiella tarda, the expression of hif-1a gene in intestine decreased (Guan et al, 2017). This phenomenon is also found in other genes.…”

A Single-Cell Transcriptome Profiling of Anterior Kidney Leukocytes From Nile Tilapia (Oreochromis niloticus)

“…The isolation of leukocytes from the AK has been widely explored by centrifugation in density gradients for a long time. Various mononuclear cell separation medium, mainly including Sepracell-MN (no longer manufactured), Percoll (GE Healthcare, Chicago, IL, USA), Histopaque ® -1077 (Sigma, St. Louis, MO, USA), and Ficoll-Paque ® PREMIUM (GE Healthcare, Chicago, IL, USA), have been used to isolate the different cell types in teleost fish (26,55,56). Among these, continuous Percoll density gradients are used to isolate different types of immune cells (monocytes/macrophages, NCCs, and DCs) roughly (44,(57)(58)(59), but Histopaque ® -1077 and Ficoll-Paque ® PREMIUM are used to obtain the leukocytes (a mixture of various immune cells, but not referring to certain cells) (26,60).…”

The evolutionary and physiological significance of the Hif pathway in teleost fishes

“…Indeed, the few studies that have measured both hif-1α mRNA and Hif-1α protein levels using homologous antibodies (e.g. Law et al, 2006;Kopp et al, 2011;Guan et al, 2017) demonstrated discrepancies between mRNA and protein levels that may vary with the duration and severity of hypoxia as well as the specific tissues being examined. A second important finding of the Soitamo et al (2001) study was the observation that although Hif-1α protein increases in cultured trout cells exposed to hypoxia, peak levels are achieved with relatively mild exposure (38 mmHg) and actually decrease at the most severe levels of hypoxia employed.…”