ITRAQ-based quantitative proteomic analysis of MG63 in response to HIF-1α inducers

HIF1α-Dependent Induction of TFRC by a Combination of Intestinal Inflammation and Systemic Iron Deficiency in Inflammatory Bowel Disease

Background and Aims: Iron deficiency (ID) is a frequent extra-intestinal manifestation in patients with Inflammatory Bowel Disease (IBD), who often do not respond to iron supplementation. Iron is a cofactor for hydroxylases that suppress the hypoxia-inducible factor-1α (HIF1α), a transcription factor regulating iron homeostasis. We hypothesized that iron deficiency affects mucosal HIF1α activity in IBD. Methods: IBD patients (n = 101) were subdivided based on iron status (ferritin levels or transferrin saturation) and systemic inflammation (C-reactive protein levels). 154 corresponding ileal and colonic biopsies were analyzed for differential expression of 20 HIF1α pathway-associated genes and related to iron and inflammation status. In vitro expression of selected HIF1α pathway genes were analyzed in wild-type and HIF1A-null Caco-2 cells. Results: Gene expression of the mucosal HIF1α pathway was most affected by intestinal location and inflammatory status. Especially, ileal mucosal TFRC expression, encoding the transferrin receptor TFR1, was increased in inflamed tissue (p < 0.001), and further enhanced in ID. Accordingly, TFRC expression in inflamed tissue associated negatively with serum iron levels, which was not observed in the non-inflamed mucosa. The HIF1α pathway agonist DMOG increased TFRC expression in Caco-2 cells, which was blunted in HIF1A-null cells. Conclusion: We demonstrate that inflammation and anatomical location primarily determine HIF1α pathway activation and downstream TFRC expression in the intestinal mucosa. IBD patients with ID may benefit from treatment with HIF1α-agonists by 1) increasing TFRC-mediated iron absorption in non-inflamed tissue and 2) decreasing mucosal inflammation, thereby improving their responsiveness to oral iron supplementation.

A unique esophageal extracellular matrix proteome alters normal fibroblast function in severe eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic TH2 disorder complicated by tissue fibrosis and loss of esophageal luminal patency. The fibrostenotic esophagus does not respond well to therapy, but profibrotic therapeutic targets are largely unclear.

OBJECTIVE

Our aim was to utilize proteomics and primary cells as a novel approach to determine relevant profibrotic factors.

METHODS

We utilized primary esophageal EoE and normal fibroblasts, their derivative extracellular matrixes (ECMs), an approach of fibroblast culture on autologous versus nonautologous ECM, and proteomics to elucidate EoE ECM proteins that dysregulate cellular function.

RESULTS

We cultured esophageal fibroblasts from normal esophagi and esophagi from patients with severe EoE on autologous versus nonautologous ECM. The EoE ECM proteome shifted normal esophageal fibroblast protein expression. Proteomic analysis demonstrated that thrombospondin-1 is detected only in the EoE ECM, is central in the EoE ECM protein-protein interactome, is found at significantly elevated levels in biopsy specimens from patients with active EoE, and induces fibroblast collagen I production.

CONCLUSION

Fibroblasts from patients with EoE secrete a unique ECM proteome that reflects their in vivo state and induces collagen I and α-smooth muscle actin protein expression from normal fibroblasts. Thrombospondin-1 is a previously unappreciated profibrotic molecule in EoE.

HIF/Ca2+/NO/ROS is critical in roxadustat treating bone fracture by stimulating the proliferation and migration of BMSCs

AIMS

Fracture site is regionally hypoxic resulting from vasculature disruption. HIF-1αplays an essential role in fracture repair. This study aims to investigate the influence of FG4592 on the femur fracture of SD rats and the proliferation, migration of BMSCs.

MATERIALS AND METHODS

After the femoral fracture model was established, computed tomography imaging and histological analyses were used to quantify bone healing and the expression of CD90, HIF-1α, VEGF were observed by means of immunohistochemistry method on Day 10 and Day 20. In addition, CCK-8 assay, transwell, flow cytometric analysis, laser confocal microscopy assay, western blot and rT-PCR were performed to text the proliferation and migration of BMSCs using FG4592.

KEY FINDINGS

In vivo, FG4592 facilitated the repair of bone fracture by increasing the number of BMSCs and cartilage formation. In vitro, FG4592 markedly improved the proliferation, migration of BMSCs via upregulation of intracellular Ca²⁺, NO and concomitant decrease of ROS. Gene silencing of HIF-1α resulted in the opposite phenomenon in BMSCs with the treatment of FG4592.

SIGNIFICANCE

The transplantation of BMSCs is the most promising candidate for the treatment of fracture non-union. We illustrated that FG4592 promoted the proliferation, migration of BMSCs via the HIF/Ca²⁺/NO/ROS pathway and further accelerated fracture healing. These results provide a deeper understanding for the mechanism of HIF in promoting fracture healing.

iTRAQ‑based quantitative proteomics analysis of the potential application of secretoneurin gene therapy for cardiac hypertrophy induced by DL‑isoproterenol hydrochloride in mice

A previous study by our group demonstrated a protective role of the neuropeptide secretoneurin (SN) in DL‑isoproterenol hydrochloride (ISO)‑induced cardiac hypertrophy in mice. To further characterize the molecular mechanism of SN treatment, an isobaric tags for relative and absolute quantification (iTRAQ)‑based quantitative proteomic analysis was applied to identify putative target proteins and molecular pathways. An SN expression vector was injected into the myocardial tissues of mice, and the animals were then subcutaneously injected with ISO (5 mg/kg/day) for 7 days to induce cardiac hypertrophy. The results of echocardiography and hemodynamic measurements indicated that the function of the heart impaired by ISO treatment was significantly ameliorated via SN gene injection. The investigation of heart proteomics was performed by iTRAQ‑based liquid chromatography‑tandem mass spectrometry analysis. A total of 2,044 quantified proteins and 15 differentially expressed proteins were associated with SN overexpression in mice with cardiac hypertrophy. Functional enrichment analysis demonstrated that these effects were possibly associated with metabolic processes. A protein‑protein interaction network analysis was constructed and the data indicated that apolipoprotein C‑III (Apoc3) was associated with the positive effect of SN on the induction of cardiac hypertrophy in mice. The present study proposed a potential mechanism of SN action on Apoc3 upregulation that may contribute to the amelioration of cardiac hypertrophy. These findings can aid the clinical application of SN in patients with cardiac hypertrophy.