Effects of CoCl2-simulated hypoxia on the expression levels of matrix metalloproteinases in renal adenocarcinoma cells and renal tubular epithelial cells

Role of the human solute carrier family 14 member 1 gene in hypoxia-induced renal cell carcinoma occurrence and its enlightenment to cancer nursing

BACKGROUND

Hypoxia is considered a critical contributor to renal cell carcinoma progression, including invasion and metastasis. However, the potential mechanisms by which it promotes invasion and metastasis have not yet been clarified. The purpose of this study was to investigate the role and mechanism of hypoxia-induced renal cell carcinoma and provide evidence-based medical proof for improvements to postoperative nursing of renal cell carcinoma patients. A total of 64 patients with renal cell carcinoma were divided into the observation group (nursing based on oxygen administration) and the control group (conventional nursing). Renal function indexes, serum inflammatory factors, and tumor markers were evaluated. The human renal cell carcinoma cell line A498 under hypoxia/normoxia was used as an experimental model in vitro and the biological characteristics and mitochondrial function of the cells were assessed.

RESULTS

Nursing based on oxygen administration decreased the value of renal function indexes, serum inflammatory factors, and tumor markers in renal cell carcinoma patients. Hypoxia was found to induce A498 cell invasion, migration, and the release of inflammatory cytokines, while repressing human solute carrier family 14 member 1 gene expression. Elevated levels of solute carrier family 14 member 1 expression induced mitochondrial reactive oxygen species accumulation, diminished the intracellular adenosine triphosphate level, and destroyed both mitochondrial membrane potential integrity and mitochondrial morphology. Overexpression of the solute carrier family 14 member 1 gene could abolish hypoxia-induced invasion, reduce the migration of A498 cells, inhibit the hypoxia-induced release of inflammatory cytokines, and arrest the cell cycle at the G1/S checkpoint.

CONCLUSIONS

These data reveal that nursing based on oxygen administration can improve the clinical efficacy of renal cell carcinoma therapies, being safe and effective. The results elucidate a mechanism wherein the solute carrier family 14 member 1 gene participates in the occurrence and development of hypoxia-induced renal cell carcinoma in a mitochondria-dependent manner.

Alterations of RNA Modification in Mouse Germ Cell-2 Spermatids Under Hypoxic Stress

Hypoxia is a known stress factor in mammals and has been shown to potentially impair male fertility, which manifests as spermatogenic dysfunction and decreased semen quality. Studies have shown that RNA modifications, the novel post-transcriptional regulators, are involved in spermatogenesis, and hypoxia-induced alterations in RNA modification in testes and sperm cells may be associated with impaired spermatogenesis in mice. However, the molecular mechanisms via which RNA modifications influence spermatogenesis under hypoxic stress conditions are unclear. In this study, we generated a mouse Germ Cell-2 spermatid (GC-2spd) hypoxia model by culturing cells in a 1% O2 incubator for 48 h or treating them with CoCl2 for 24 h. The hypoxia treatment significantly inhibited proliferation and induced apoptosis in GC-2spd cells. The RNA modification signatures of total RNAs (2 types) and differentially sized RNA fragments (7 types of approximately 80 nt-sized tRNAs; 9 types of 17–50 nt-sized sncRNAs) were altered, and tRNA stability was partially affected. Moreover, the expression profiles of sncRNAs, such as microRNAs, tsRNAs, rsRNAs, and ysRNAs, were significantly regulated, and this might be related to the alterations in RNA modification and subsequent transcriptomic changes. We comprehensively analyzed alterations in RNA modification signatures in total RNAs, tRNAs (approximately 80 nt), and small RNAs (17–50 nt) as well as the expression profiles of sncRNAs and transcriptomes in hypoxia-treated GC-2spd cells; our data suggested that RNA modifications may be involved in cellular responses under hypoxic stress conditions and could provide a basis for a better understanding of the molecular mechanisms underlying male infertility.

Regenerative Activities of ROS-Modulating Trace Metals in Subcutaneously Implanted Biodegradable Cryogel

Divalent trace metals (TM), especially copper (Cu), cobalt (Co) and zinc (Zn), are recognized as essential microelements for tissue homeostasis and regeneration. To achieve a balance between therapeutic activity and safety of administered TMs, effective gel formulations of TMs with elucidated regenerative mechanisms are required. We studied in vitro and in vivo effects of biodegradable macroporous cryogels doped with Cu, Co or Zn in a controllable manner. The extracellular ROS generation by metal dopants was assessed and compared with the intracellular effect of soluble TMs. The stimulating ability of TMs in the cryogels for cell proliferation, differentiation and cytokine/growth factor biosynthesis was characterized using HSF and HUVEC primary human cells. Multiple responses of host tissues to the TM-doped cryogels upon subcutaneous implantation were characterized taking into account the rate of biodegradation, production of HIF-1α/matrix metalloproteinases and the appearance of immune cells. Cu and Zn dopants did not disturb the intact skin organization while inducing specific stimulating effects on different skin structures, including vasculature, whereas Co dopant caused a significant reorganization of skin layers, the appearance of multinucleated giant cells, along with intense angiogenesis in the dermis. The results specify and compare the prooxidant and regenerative potential of Cu, Co and Zn-doped biodegradable cryogels and are of particular interest for the development of advanced bioinductive hydrogel materials for controlling angiogenesis and soft tissue growth.

HIF-1α ameliorates tubular injury in diabetic nephropathy via HO-1-mediated control of mitochondrial dynamics

Objectives

In diabetic nephropathy (DN), hypoxia‐inducible factor‐1α (HIF‐1α) activation in tubular cells plays an important protective role against kidney injury. The effects may occur via the target genes of HIF‐1α, such as haem oxygenase‐1 (HO‐1), but the exact mechanisms are incompletely understood.

Materials and methods

Mice with proximal tubule‐specific knockout of HIF‐1α (PT‐HIF‐1α^−/− mice) were generated, and diabetes was induced in these mice by streptozotocin (STZ) injection. In addition, to mimic a hypoxic state, cobaltous chloride (CoCl₂) was applied to HK‐2 cells.

Results

Our study first verified that conditional knockout of HIF‐1α worsened tubular injury in DN; additionally, aggravated kidney dysfunction, renal histopathological alterations, mitochondrial fragmentation, ROS accumulation and apoptosis were observed in diabetic PT‐HIF‐1α^−/− mice. In vitro study showed that compared to control group, HK‐2 cells cultured under hypoxic ambiance displayed increased mitochondrial fragmentation, ROS production, mitochondrial membrane potential loss and apoptosis. These increases were reversed by overexpression of HIF‐1α or treatment with a HO‐1 agonist. Importantly, cotreatment with a HIF‐1α inhibitor and a HO‐1 agonist rescued the HK‐2 cells from the negative impacts of the HIF‐1α inhibitor.

Conclusions

These data revealed that HIF‐1α exerted a protective effect against tubular injury in DN, which could be mediated via modulation of mitochondrial dynamics through HO‐1 upregulation.