Background: To explore the roles of HIF1α- and HIF2α-regulated BNIP3 in hypoxia-induced injury of neurons.
Methods: The sera of neonates with hypoxic-ischemic encephalopathy (HIE) within 24 h after birth and full-term healthy newborns (n = 40) were collected. The BNIP3 levels were detected by ELISA. AGE1.HN cells were cultured in 1% O at 37 °C. The apoptosis of cells treated with 1, 5 and 10 ng/ml BNIP3 for 48 h was detected by flow cytometry. The proliferation of cells transfected with siBNIP3 was detected by CCK-8 assay. The mRNA level of BNIP3 in cells under hypoxic conditions was measured by RT-PCR. The protein level of BNIP3 in cells cultured under hypoxic conditions after pretreatment with HIF1α or HIF2α inhibitor was measured by Western blot.
Results: The serum BNIP3 concentration of HIE neonates ((4.5 ± 2.1) ng/ml) was significantly higher than that of healthy neonates ((1.2 ± 0.5) ng/ml) (P < 0.001). Compared with untreated group, the number of apoptotic AGE1.HN cells treated with BNIP3 significantly increased (P < 0.05). Under hypoxic conditions (1%), the mRNA and protein levels of BNIP3 increased significantly with prolonged time. After pretreatment with HIF1α or HIF2α inhibitor and hypoxic culture, BNIP3 expression was significantly lower than that of cells hypoxically cultured only. Inhibiting the expression of HIF1α or HIF2α or transfecting with siBNIP3 before hypoxic treatment significantly reduced the number of apoptotic cells. Under hypoxic conditions, HIF1α or HIF2α bound BNIP3 promoter, which did not occur under normal culture conditions. HIF1α or HIF2α was significantly enriched near the hypoxia response element (HRE) site of BNIP3 promoter.
Conclusions: BNIP3 was involved in the apoptosis of cells undergoing HIE. The HRE site of BNIP3 promoter bound HIF to promote its transcription.
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http://dx.doi.org/10.1016/j.prp.2019.01.022 | DOI Listing |
J Comp Physiol B
July 2021
Department of Biology, University of Ottawa, Gendron Hall, 30 Marie Curie Private, Ottawa, ON, K1N 6N5, Canada.
Previous studies have demonstrated that hypoxia tolerance is improved in zebrafish (Danio rerio) larvae after prior exposure to lowered ambient O levels. Such improved hypoxia performance was attributed in part, to increased levels of hypoxia-inducible factor 1α (Hif-1α) exerting downstream effects on various physiological processes including promotion of trunk skin angiogenesis. Since O uptake ([Formula: see text]) in larvae is facilitated largely by O diffusion across the skin, enhanced cutaneous vascularization is expected to enhance [Formula: see text] during hypoxia and thus contribute to improved hypoxia tolerance.
View Article and Find Full Text PDFSci Rep
October 2020
College of Fisheries, National Demonstration Center for Experimental Aquaculture Education, Huazhong Agricultural University, Wuhan, 430070, China.
Hypoxia-inducible factor 1 (HIF-1) functions as a master regulator of the cellular response to hypoxic stress. Two HIF-1α paralogs, HIF-1αA and HIF-1αB, were generated in euteleosts by the specific, third round of genome duplication, but one paralog was later lost in most families with the exception of cyprinid fish. How these duplicates function in mitochondrial regulation and whether their preservation contributes to the hypoxia tolerance demonstrated by cyprinid fish in freshwater environments is not clear.
View Article and Find Full Text PDFCurr Neurovasc Res
July 2021
Jiangxi Engineering Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases, Ji'an, Jiangxi, China.
Background: Curcumin has anti-inflammatory, antioxidant and anticancer properties. Despite the considerable evidence showing that curcumin is an efficacious and safe compound for multiple medicinal benefits, there are some demerits with respect to the therapeutic effectiveness of curcumin, namely, poor stability and solubility, and its role in angiogenesis in vivo is still not yet clear. More recently, the biodegradable polymer nanoparticles have been developed.
View Article and Find Full Text PDFJ Exp Biol
January 2019
Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada.
Hypoxia-inducible factor (Hif) 1α, an extensively studied transcription factor, is involved in the regulation of many biological processes in hypoxia including the hypoxic ventilatory response. In zebrafish, there are two paralogs of Hif-1α (Hif-1A and Hif-1B), but little is known about the specific roles or potential sub-functionalization of the paralogs in response to hypoxia. Using knockout lines of Hif-1α paralogs, we examined their involvement in the hypoxic ventilatory response, measured as ventilation frequency () in larval and adult zebrafish ().
View Article and Find Full Text PDFJ Biol Chem
October 2018
From the State Key Laboratory of Freshwater Ecology and Biotechnology and
Many aerobic organisms have developed molecular mechanism to tolerate hypoxia, but the specifics of these mechanisms remain poorly understood. It is important to develop genetic methods that confer increased hypoxia tolerance to intensively farmed aquatic species, as these are maintained in environments with limited available oxygen. As an asparaginyl hydroxylase of hypoxia-inducible factors (HIFs), factor inhibiting HIF (FIH) inhibits transcriptional activation of hypoxia-inducible genes by blocking the association of HIFs with the transcriptional coactivators CREB-binding protein (CBP) and p300.
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