Polymorphic variation of hypoxia inducible factor-1 A (HIF1A) gene might contribute to the development of knee osteoarthritis: a pilot study

Fibroblast-like synoviocytes (FLSs) are the main effector cells of knee osteoarthritis (KOA) synovial fibrosis. Our last report showed that NLRP1 and NLRP3 inflammasomes may mediate LPS/ATP-induced FLSs pyroptosis in KOA. In the present study, we found an elevated hypoxia-inducible factor-1α (HIF-1α) level in the synovial tissue of KOA model rats, and inhibiting the increase of HIF-1α could improve synovial fibrosis in rats. Subsequently, we established LPS/ATP-induced model in FLSs mimicking the inflammatory environment of KOA. FLSs transfected with siRNA HIF-1α showed a reduced cell death; meanwhile, the relative expression of pyroptosis-related proteins was also downregulated. Additionally, FLSs transfected with or without siRNA GSDMD were exposed to hypoxia. GSDMD silencing can significantly reduce both gene and protein levels of fibrogenic markers transforming growth factor-β (TGF-β), procollagen-lysine, 2-oxoglutarate 5-dioxygenase2 (PLOD2), collagen type I α1 chain (COL1A1), and tissue inhibitor of metalloproteinases 1 (TIMP1). Taken together, our findings indicate that increased HIF-1α is highly involved in the KOA synovial fibrosis. Moreover, elevated HIF-1α may aggravate synovial fibrosis via FLS pyroptosis.

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Vascular adaptations to hypoxia: molecular and cellular mechanisms regulating vascular tone

Essays in Biochemistry ◽

10.1042/bse0430105 ◽

2007 ◽

Vol 43 ◽

pp. 105-120 ◽

Cited By ~ 8

Author(s):

Michael L. Paffett ◽

Benjimen R. Walker

Keyword(s):

Vascular Tone ◽

Cellular Proliferation ◽

Hypoxic Pulmonary Vasoconstriction ◽

Hypoxia Inducible Factor ◽

Systemic Circulation ◽

Cellular Mechanisms ◽

Hypoxia Inducible Factor 1 ◽

Pulmonary Vasoconstriction ◽

Adaptive Mechanisms ◽

Adaptive Processes

Several molecular and cellular adaptive mechanisms to hypoxia exist within the vasculature. Many of these processes involve oxygen sensing which is transduced into mediators of vasoconstriction in the pulmonary circulation and vasodilation in the systemic circulation. A variety of oxygen-responsive pathways, such as HIF (hypoxia-inducible factor)-1 and HOs (haem oxygenases), contribute to the overall adaptive process during hypoxia and are currently an area of intense research. Generation of ROS (reactive oxygen species) may also differentially regulate vascular tone in these circulations. Potential candidates underlying the divergent responses between the systemic and pulmonary circulations may include Nox (NADPH oxidase)-derived ROS and mitochondrial-derived ROS. In addition to alterations in ROS production governing vascular tone in the hypoxic setting, other vascular adaptations are likely to be involved. HPV (hypoxic pulmonary vasoconstriction) and CH (chronic hypoxia)-induced alterations in cellular proliferation, ionic conductances and changes in the contractile apparatus sensitivity to calcium, all occur as adaptive processes within the vasculature.

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Hypoxia Inducible Factor-1 (HIF-1) mediates trophoblast differentiation induced by oxygen tension and is overexpressed in preeclampsia

Journal of the Society for Gynecologic Investigation ◽

10.1016/s1071-5576(97)86116-3 ◽

1998 ◽

Vol 5 (1) ◽

pp. 48A-48A

Author(s):

I CANIGGIA ◽

M KULISZEWSKI ◽

S LYE ◽

M POST

Keyword(s):

Oxygen Tension ◽

Hypoxia Inducible Factor ◽

Trophoblast Differentiation ◽

Hypoxia Inducible Factor 1

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TAp73 opposes tumor angiogenesis by promoting hypoxia-inducible factor 1α degradation

10.31234/osf.io/v24zc ◽

2020 ◽

Author(s):

Lungwani Muungo

Keyword(s):

Cancer Progression ◽

Hypoxia Inducible Factor ◽

Tumor Hypoxia ◽

Human Lung Cancer ◽

Regulatory Subunit ◽

Patients With Cancer ◽

Hypoxia Inducible Factor 1 ◽

Chemically Induced ◽

Induced Tumors ◽

Patient Prognosis

Tumor hypoxia and hypoxia-inducible factor 1 (HIF-1) activationare associated with cancer progression. Here, we demonstrate thatthe transcription factor TAp73 opposes HIF-1 activity through anontranscriptional mechanism, thus affecting tumor angiogenesis.TAp73-deficient mice have an increased incidence of spontaneousand chemically induced tumors that also display enhanced vascularization.Mechanistically, TAp73 interacts with the regulatory subunit(α) of HIF-1 and recruits mouse double minute 2 homolog intothe protein complex, thus promoting HIF-1α polyubiquitination andconsequent proteasomal degradation in an oxygen-independentmanner. In human lung cancer datasets, TAp73 strongly predictsgood patient prognosis, and its expression is associated with lowHIF-1 activation and angiogenesis. Our findings, supported by invivo and clinical evidence, demonstrate a mechanism for oxygenindependentHIF-1 regulation, which has important implicationsfor individualizing therapies in patients with cancer.

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