scholarly journals Cathepsin L, a Target of Hypoxia-Inducible Factor-1-α, Is Involved in Melanosome Degradation in Melanocytes

2021 ◽  
Vol 22 (16) ◽  
pp. 8596
Author(s):  
Ji Young Kim ◽  
Eun Jung Lee ◽  
Yuri Ahn ◽  
Sujin Park ◽  
Yu Jeong Bae ◽  
...  
Keyword(s):  
Target Gene ◽  
Target Genes ◽  
Cathepsin L ◽  
Hypoxia Inducible Factor ◽  
Luciferase Reporter ◽  
Lysosomal Activity ◽  
Hypoxia Inducible Factor 1 ◽  
Lysosomal Protease ◽  
Hypoxic Conditions ◽  
Novel Target

Hypoxic conditions induce the activation of hypoxia-inducible factor-1α (HIF-1α) to restore the supply of oxygen to tissues and cells. Activated HIF-1α translocates into the nucleus and binds to hypoxia response elements to promote the transcription of target genes. Cathepsin L (CTSL) is a lysosomal protease that degrades cellular proteins via the endolysosomal pathway. In this study, we attempted to determine if CTSL is a hypoxia responsive target gene of HIF-1α, and decipher its role in melanocytes in association with the autophagic pathway. The results of our luciferase reporter assay showed that the expression of CTSL is transcriptionally activated through the binding of HIF1-α at its promoter. Under autophagy-inducing starvation conditions, HIF-1α and CTSL expression is highly upregulated in melan-a cells. The mature form of CTSL is closely involved in melanosome degradation through lysosomal activity upon autophagosome–lysosome fusion. The inhibition of conversion of pro-CTSL to mature CTSL leads to the accumulation of gp100 and tyrosinase in addition to microtubule-associated protein 1 light chain 3 (LC3) II, due to decreased lysosomal activity in the autophagic pathway. In conclusion, we have identified that CTSL, a novel target of HIF-1α, participates in melanosome degradation in melanocytes through lysosomal activity during autophagosome–lysosome fusion.

scholarly journals NCX1 Is a Novel Target Gene for Hypoxia-Inducible Factor-1 in Ischemic Brain Preconditioning

Stroke ◽  
2011 ◽  
Vol 42 (3) ◽  
pp. 754-763 ◽  
Author(s):  
Valeria Valsecchi ◽  
Giuseppe Pignataro ◽  
Annalisa Del Prete ◽  
Rossana Sirabella ◽  
Carmela Matrone ◽  
...  
Keyword(s):  
Target Gene ◽  
Hypoxia Inducible Factor ◽  
Ischemic Brain ◽  
Hypoxia Inducible Factor 1 ◽  
Novel Target ◽  
Brain Preconditioning

scholarly journals Radiolabeled Probes Targeting Hypoxia-Inducible Factor-1-Active Tumor Microenvironments

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Masashi Ueda ◽  
Hideo Saji
Keyword(s):  
Clinical Studies ◽  
Target Genes ◽  
Hypoxia Inducible Factor ◽  
Active Regions ◽  
Therapy Resistance ◽  
Current Status ◽  
Tumor Microenvironments ◽  
Hypoxia Inducible Factor 1 ◽  
Hypoxic Conditions ◽  
Expression Of Genes

Because tumor cells grow rapidly and randomly, hypoxic regions arise from the lack of oxygen supply in solid tumors. Hypoxic regions in tumors are known to be resistant to chemotherapy and radiotherapy. Hypoxia-inducible factor-1 (HIF-1) expressed in hypoxic regions regulates the expression of genes related to tumor growth, angiogenesis, metastasis, and therapy resistance. Thus, imaging of HIF-1-active regions in tumors is of great interest. HIF-1 activity is regulated by the expression and degradation of itsαsubunit (HIF-1α), which is degraded in the proteasome under normoxic conditions, but escapes degradation under hypoxic conditions, allowing it to activate transcription of HIF-1-target genes. Therefore, to image HIF-1-active regions, HIF-1-dependent reporter systems and injectable probes that are degraded in a manner similar to HIF-1αhave been recently developed and used in preclinical studies. However, no probe currently used in clinical practice directly assesses HIF-1 activity. Whether the accumulation of18F-FDG or18F-FMISO can be utilized as an index of HIF-1 activity has been investigated in clinical studies. In this review, the current status of HIF-1 imaging in preclinical and clinical studies is discussed.

scholarly journals Astrocyte-specific hypoxia-inducible factor 1 (HIF-1) does not disrupt the endothelial barrier during hypoxia in vitro

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Julia Baumann ◽  
Chih-Chieh Tsao ◽  
Sheng-Fu Huang ◽  
Max Gassmann ◽  
Omolara O. Ogunshola
Keyword(s):  
Tight Junction ◽  
Target Genes ◽  
Hypoxia Inducible Factor ◽  
Conditioned Media ◽  
Supporting Evidence ◽  
Quiescent State ◽  
Paracrine Signaling ◽  
Hypoxia Inducible Factor 1 ◽  
Hypoxic Conditions ◽  
Cell Cycling

Abstract Background Astrocytes (AC) are essential for brain homeostasis. Much data suggests that AC support and protect the vascular endothelium, but increasing evidence indicates that during injury conditions they may lose their supportive role resulting in endothelial cell activation and BBB disturbance. Understanding the triggers that flip this switch would provide invaluable information for designing new targets to modulate the brain vascular compartment. Hypoxia-inducible factor-1 (HIF-1) has long been assumed to be a culprit for barrier dysfunction as a number of its target genes are potent angiogenic factors. Indeed AC themselves, reservoirs of an array of different growth factors and molecules, are frequently assumed to be the source of such molecules although direct supporting evidence is yet to be published. Being well known reservoirs of HIF-1 dependent angiogenic molecules, we asked if AC HIF-1 dependent paracrine signaling drives brain EC disturbance during hypoxia. Methods First we collected conditioned media from control and siRNA-mediated HIF-1 knockdown primary rat AC that had been exposed to normoxic or hypoxic conditions. The conditioned media was then used to culture normoxic and hypoxic (1% O2) rat brain microvascular EC (RBE4) for 6 and 24 h. Various activation parameters including migration, proliferation and cell cycling were assessed and compared to untreated controls. In addition, tight junction localization and barrier stability per se (via permeability assay) was evaluated. Results AC conditioned media maintained both normoxic and hypoxic EC in a quiescent state by suppressing EC metabolic activity and proliferation. By FACs we observed reduced cell cycling with an increased number of cells in G0 phase and reduced cell numbers in M phase compared to controls. EC migration was also blocked by AC conditioned media and in correlation hypoxic tight junction organization and barrier functionality was improved. Surprisingly however, AC HIF-1 deletion did not impact EC responses or barrier stability during hypoxia. Conclusions This study demonstrates that AC HIF-1 dependent paracrine signaling does not contribute to AC modulation of EC barrier function under normoxic or hypoxic conditions. Thus other cell types likely mediate EC permeability in stress scenarios. Our data does however highlight the continuous protective effect of AC on the barrier endothelium. Exploring these protective mechanisms in more detail will provide essential insight into ways to prevent barrier disturbance during injury and disease.

scholarly journals Anti-Cancer Activity of Phytochemicals Targeting Hypoxia-Inducible Factor-1 Alpha

2021 ◽  
Vol 22 (18) ◽  
pp. 9819
Author(s):  
Ba Da Yun ◽  
Seung Wan Son ◽  
Soo Young Choi ◽  
Hyo Jeong Kuh ◽  
Tae-Jin Oh ◽  
...  
Keyword(s):  
Poor Prognosis ◽  
Target Genes ◽  
Hypoxia Inducible Factor ◽  
Therapeutic Resistance ◽  
Hypoxia Inducible Factor 1 ◽  
Hypoxic Conditions ◽  
Cellular Factors ◽  
Anti Cancer ◽  
Cancer Types ◽  
Cancer Activity

Hypoxia-inducible factor-1 alpha (HIF-1α) is overexpressed in cancer, leading to a poor prognosis in patients. Diverse cellular factors are able to regulate HIF-1α expression in hypoxia and even in non-hypoxic conditions, affecting its progression and malignant characteristics by regulating the expression of the HIF-1α target genes that are involved in cell survival, angiogenesis, metabolism, therapeutic resistance, et cetera. Numerous studies have exhibited the anti-cancer effect of HIF-1α inhibition itself and the augmentation of anti-cancer treatment efficacy by interfering with HIF-1α-mediated signaling. The anti-cancer effect of plant-derived phytochemicals has been evaluated, and they have been found to possess significant therapeutic potentials against numerous cancer types. A better understanding of phytochemicals is indispensable for establishing advanced strategies for cancer therapy. This article reviews the anti-cancer effect of phytochemicals in connection with HIF-1α regulation.

scholarly journals Hypoxia-inducible factor 1α induces osteo/odontoblast differentiation of human dental pulp stem cells via Wnt/β-catenin transcriptional cofactor BCL9

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Shion Orikasa ◽  
Nobuyuki Kawashima ◽  
Kento Tazawa ◽  
Kentaro Hashimoto ◽  
Keisuke Sunada-Nara ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dental Pulp ◽  
Target Genes ◽  
Hypoxia Inducible Factor ◽  
Dental Pulp Stem Cells ◽  
Pulp Tissue ◽  
Odontoblast Differentiation ◽  
Hypoxia Inducible Factor 1Α ◽  
Hypoxic Conditions

AbstractAccelerated dental pulp mineralization is a common complication in avulsed/luxated teeth, although the mechanisms underlying this remain unclear. We hypothesized that hypoxia due to vascular severance may induce osteo/odontoblast differentiation of dental pulp stem cells (DPSCs). This study examined the role of B-cell CLL/lymphoma 9 (BCL9), which is downstream of hypoxia-inducible factor 1α (HIF1α) and a Wnt/β-catenin transcriptional cofactor, in the osteo/odontoblastic differentiation of human DPSCs (hDPSCs) under hypoxic conditions. hDPSCs were isolated from extracted healthy wisdom teeth. Hypoxic conditions and HIF1α overexpression induced significant upregulation of mRNAs for osteo/odontoblast markers (RUNX2, ALP, OC), BCL9, and Wnt/β-catenin signaling target genes (AXIN2, TCF1) in hDPSCs. Overexpression and suppression of BCL9 in hDPSCs up- and downregulated, respectively, the mRNAs for AXIN2, TCF1, and the osteo/odontoblast markers. Hypoxic-cultured mouse pulp tissue explants showed the promotion of HIF1α, BCL9, and β-catenin expression and BCL9-β-catenin co-localization. In addition, BCL9 formed a complex with β-catenin in hDPSCs in vitro. This study demonstrated that hypoxia/HIF1α-induced osteo/odontoblast differentiation of hDPSCs was partially dependent on Wnt/β-catenin signaling, where BCL9 acted as a key mediator between HIF1α and Wnt/β-catenin signaling. These findings may reveal part of the mechanisms of dental pulp mineralization after traumatic dental injury.

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