Macrophage migration inhibitory factor is regulated by HIF-1α and cAMP and promotes renal cyst cell proliferation in a macrophage-independent manner

Hypermethylation of BMPR2 and TGF-β Promoter Regions in Tibetan Patients with High-Altitude Polycythemia at Extreme Altitude

Although the expression of many genes is associated with adaptation to high-altitude hypoxic environments, the role of epigenetics in the response to this harsh environmental stress is currently unclear. We explored whether abnormal DNA promoter methylation levels of six genes, namely, ABCA1, SOD2, AKT1, VEGFR2, TGF-β, and BMPR2, affect the occurrence and development of high-altitude polycythemia (HAPC) in Tibetans. The methylation levels of HAPC and the control group of 130 Tibetans from very high altitudes (> 4500 m) were examined using quantitative methylation-specific real-time PCR (QMSP). Depending on the type of data, the Pearson chi-square test, Wilcoxon rank-sum test, and Fisher exact test were used to assess the differences between the two groups. The correlation between the methylation levels of each gene and the hemoglobin content was explored using a linear mixed model. Our experiment revealed that the methylation levels of the TGF-β and BMPR2 genes differed significantly in the two groups (p < 0.05) and linear mixed model analysis showed that the correlation between the hemoglobin and methylation of ABCA1, TGF-β, and BMPR2 was statistically significant (p < 0.05). Our study suggests that levels of TGF-β and BMPR2 methylation are associated with the occurrence of HAPC in extreme-altitude Tibetan populations among 6 selected genes. Epigenetics may be involved in the pathogenesis of HAPC, and future experiments could combine gene and protein levels to verify the diagnostic value of TGF-β and BMPR2 methylation levels in HAPC.

The roles of macrophage migration inhibitory factor in retinal diseases

Macrophage migration inhibitory factor (MIF), a multifunctional cytokine, is secreted by various cells and participates in inflammatory reactions, including innate and adaptive immunity. There are some evidences that MIF is involved in many vitreoretinal diseases. For example, MIF can exacerbate many types of uveitis; measurements of MIF levels can be used to monitor the effectiveness of uveitis treatment. MIF also alleviates trauma-induced and glaucoma-induced optic nerve damage. Furthermore, MIF is critical for retinal/choroidal neovascularization, especially complex neovascularization. MIF exacerbates retinal degeneration; thus, anti-MIF therapy may help to mitigate retinal degeneration. MIF protects uveal melanoma from attacks by natural killer cells. The mechanism underlying the effects of MIF in these diseases has been demonstrated: it binds to cluster of differentiation 74, inhibits the c-Jun N-terminal kinase pathway, and triggers mitogen-activated protein kinases, extracellular signal-regulated kinase-1/2, and the phosphoinositide-3-kinase/Akt pathway. MIF also upregulates Toll-like receptor 4 and activates the nuclear factor kappa-B signaling pathway. This review focuses on the structure and function of MIF and its receptors, including the effects of MIF on uveal inflammation, retinal degeneration, optic neuropathy, retinal/choroidal neovascularization, and uveal melanoma.

DLGAP5 promotes gallbladder cancer migration and tumor-associated macrophage M2 polarization by activating cAMP

BACKGROUND

Although disc large associated protein family (DLGAP5) has been reported to be involved in a variety of tumor pathologic processes, its expression and mechanism in gallbladder cancer (GBC) are still uncertain. Macrophages were divided into M1 and M2 macrophages. TAM is more closely defined as M2 polarized macrophages, which plays a key role in cancer progression.

OBJECTIVE

To clarify the role of disc large associated protein family (DLGAP5) in gallbladder cancer (GBC) progression and investigate the mechanism.

METHODS

Differential genes in 10 normal paracancer tissues and 10 GBC tissues in GSE139682 from NCBI-GEO were analyzed by R language. Bioinformation analysis and clinical sample analysis were performed to detect DLGAP5 expression in GBC and its correlation with prognosis. CCK-8, EDU, transwell, wound closure, and Immunoblot were performed to detect its effects on the function of GBC cells. GST-pulldown showed the direct interact between DLGAP5 and cAMP. Macrophage polarization assay was further conducted to detect the effects of DLGAP5 on macrophage M2 polarization. The tumor growth assays were further conducted to confirm its role in mice.

RESULTS

Biological analysis and clinical samples confirmed that DLGAP5 was increased in GBC and strongly related to poor prognosis in patients with GBC. After overexpression of DLGAP5 in GBC cell lines, such as GBC-SD and NOZ cells, cell proliferation and migration were enhanced, and macrophages were polarized to M2. However, after DLGAP5 is knocked down, there is opposite effect. Mechanistically, DLGAP5 promotes the growth and migration of GBC-SD and NOZ cells and the M2 polarization of THP-1-derived macrophages by activating cyclic adenosine monophosphate (cAMP) pathway. In vivo, GBC-SD with DLGAP5 knockdown was subcutaneously injected into nude mice. It was found that after DLGAP5 knockdown, both tumor volume and tumor were reduced, and indicators related to proliferation and M2 polarization decreased.

CONCLUSION

Our study shows that DLGAP5 is significantly elevated in GBC and is strongly related to poor prognosis in patients with GBC. DLGAP5 promotes GBC proliferation, migration, and M2 polarization of macrophages through cAMP pathway, which provides a theoretical basis for the treatment of GBC and may become a promising therapeutic target.

Urinary Biomarkers in Monitoring the Progression and Treatment of Autosomal Dominant Polycystic Kidney Disease-The Promised Land?

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney disease, and it leads to end-stage renal disease (ESRD). The clinical manifestations of ADPKD are variable, with extreme differences observable in its progression, even among members of the same family with the same genetic mutation. In an age of new therapeutic options, it is important to identify patients with rapidly progressive evolution and the risk factors involved in the disease's poor prognosis. As the pathophysiological mechanisms of the formation and growth of renal cysts have been clarified, new treatment options have been proposed to slow the progression to end-stage renal disease. Furthermore, in addition to the conventional factors (PKD1 mutation, hypertension, proteinuria, total kidney volume), increasing numbers of studies have recently identified new serum and urinary biomarkers of the disease's progression, which are cheaper and more easily to dosing from the early stages of the disease. The present review discusses the utility of new biomarkers in the monitoring of the progress of ADPKD and their roles in new therapeutic approaches.

Macrophage migration inhibitory factor (MIF) inhibitor iSO-1 promotes staphylococcal protein A-induced osteogenic differentiation by inhibiting NF-κB signaling pathway

BACKGROUND

Osteomyelitis is among the most difficult to treat diseases in the field of orthopedics, and there is a lack of effective treatment modalities. Exploring the mechanisms of its development is beneficial for finding molecular targets for treatment. Increasing evidence suggests that macrophage migration inhibitory factor (MIF), as a proinflammatory mediator, is not only involved in various pathophysiological processes of inflammation but also plays an important role in osteogenic differentiation, while its specific regulatory mechanism in osteomyelitis remains unclear.

METHODS

In the present study, staphylococcal protein A (SPA)-treated rat bone marrow mesenchymal stem cells (rBMSCs) were used to construct cell models of osteomyelitis. Rat and cell models of osteomyelitis were used to validate the expression levels of MIF, and to further explore the regulatory mechanisms of the MIF inhibitor methyl ester of (S, R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid (iSO-1) and MIF knockdown on cell model of osteomyelitis toward osteogenic differentiation.

RESULTS

We found that the expression level of MIF was upregulated in rat and cell models of osteomyelitis and subsequently demonstrated by the GSE30119 dataset that the expression level of MIF was also significantly upregulated in patients with osteomyelitis. Furthermore, SPA promotes MIF expression in rBMSCs while inhibiting the expression of osteogenic-related genes such as Runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), osteopontin (OPN) and collagen type-1 (COL-1) through activation of the nuclear factor kappa-B (NF-κB) pathway. In vivo, we further demonstrated that local injection of iSO-1 significantly increased the osteogenic activity in rat model of osteomyelitis. Importantly, we also demonstrated that MIF knockdown and the MIF inhibitor iSO-1 reversed the SPA-mediated inhibition of osteogenic differentiation of rBMSCs by inhibiting the activation of the NF-κB pathway, as evidenced by the upregulation of osteogenic-related gene expression and enhanced bone mineralization.

CONCLUSION

ISO-1 and MIF knockdown can reverse the SPA-mediated inhibition of osteogenic differentiation in the rBMSCs model of osteomyelitis by inhibiting the NF-κB signaling pathway, providing a potential target for the treatment of osteomyelitis.

Macrophage migration inhibitory factor in acute kidneyinjury

Acute kidney injury (AKI) is a complex clinical syndrome with multiple etiologies and pathogenesis, which lacks early biomarkers and targeted therapy. Recently, macrophage migration inhibitory factor (MIF) family protein have received increasing attention owing to its pleiotropic protein molecule character in acute kidney injury, where it performed a dual role in the pathological process. macrophage migration inhibitory factor and macrophage migration inhibitory factor-2 are released into the peripheral circulation when Acute kidney injury occurs and interact with various cellular pathways. On the one hand, macrophage migration inhibitory factor exerts a protective effect in anti-oxidation and macrophage migration inhibitory factor-2 promotes cell proliferation and ameliorates renal fibrosis. On the other hand, macrophage migration inhibitory factor aggravates renal injury as an upstream inflammation factor. Herein, we provide an overview on the biological role and possible mechanisms of macrophage migration inhibitory factor and macrophage migration inhibitory factor-2 in the process of Acute kidney injury and the clinical application prospects of macrophage migration inhibitory factor family proteins as a potential therapeutic target.

Macrophage Migration Inhibitory Factor (MIF) as a Stress Molecule in Renal Inflammation

Renal inflammation is an initial pathological process during progressive renal injury regardless of the initial cause. Macrophage migration inhibitory factor (MIF) is a truly proinflammatory stress mediator that is highly expressed in a variety of both inflammatory cells and intrinsic kidney cells. MIF is released from the diseased kidney immediately upon stimulation to trigger renal inflammation by activating macrophages and T cells, and promoting the production of proinflammatory cytokines, chemokines, and stress molecules via signaling pathways involving the CD74/CD44 and chemokine receptors CXCR2, CXCR4, and CXCR7 signaling. In addition, MIF can function as a stress molecule to counter-regulate the immunosuppressive effect of glucocorticoid in renal inflammation. Given the critical position of MIF in the upstream inflammatory cascade, this review focuses on the regulatory role and molecular mechanisms of MIF in kidney diseases. The therapeutic potential of targeting MIF signaling to treat kidney diseases is also discussed.

Hypoxia-Inducible Factor Stabilization as an Emerging Therapy for CKD-Related Anemia: Report From a Scientific Workshop Sponsored by the National Kidney Foundation

The National Kidney Foundation convened an interdisciplinary international workshop in March 2019 to discuss the potential role of a new class of agents for the treatment of anemia in patients with chronic kidney disease (CKD): the hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs). International experts with expertise in physiology, biochemistry, structural chemistry, translational medicine and clinical management of anemia participated. Participants reviewed the unmet needs of current anemia treatment, the biology of hypoxia-inducible factor, the pharmacology of prolyl hydroxylase inhibitors, and the results of phase 2 clinical trials of HIF-PHIs among patients with both non-dialysis dependent and dialysis-dependent CKD. The results of key phase 3 clinical trials of HIF-PHIs in the public domain as of this writing are also presented in this article although they appeared after the workshop was completed. Participants in the workshop developed a number of recommendations for further examination of HIF-PHIs which are summarized in this article and include long-term safety issues, potential benefits, and practical considerations for implementation including patient and provider education.