ICBP90 Regulates MIF Expression, Glucocorticoid Sensitivity, and Apoptosis at the MIF Immune Susceptibility Locus

[Myeloid-derived suppressor cells as important factors and potential targets for breast cancer progression]

Recurrence and metastasis remain the leading cause of death in breast cancer patients due to the lack of effective treatment. A microenvironment suitable for cancer cell growth, referred to as pre-metastatic niche (PMN), is formed in distant organs before metastasis occurs. Myeloid-derived suppressor cells (MDSCs) are a heterogenous population of immature myeloid cells with immunosuppressive effects. They can expand in large numbers in breast cancer patients and participate in the formation of PMN. MDSCs can remodel the extracellular matrix of pulmonary vascular endothelial cells and recruit cancer stem cells to promote the lung metastasis of breast cancer. Furthermore, MDSCs facilitate immune evasion of breast cancer cells to impact the efficacy of immunotherapy. It is proposed that MDSCs represent a potential therapeutic target for the inhibition of recurrence and metastasis in breast cancer. Therapeutic strategies targeting MDSCs have shown promising efficacy in preclinical studies and clinical trials. This review presents a summary of the principal factors involved in the recruitment and activation of MDSCs during the formation of PMN, and outlines MDSCs functions such as immunosuppression and the current targeted therapies against MDSCs, aiming to provide new ideas for the treatment of distant metastases in breast cancer.

A small-molecule allele-selective transcriptional inhibitor of the MIF immune susceptibility locus

Functional variants of the gene for the cytokine macrophage migration inhibitory factor (MIF) are defined by a 4-nucleotide promoter microsatellite (-794 CATT5-8, rs5844572) and confer risk for autoimmune, infectious, and oncologic diseases. We describe herein the discovery of a prototypic, small molecule inhibitor of MIF transcription with selectivity for high microsatellite repeat number and correspondingly high gene expression. Utilizing a high-throughput luminescent proximity screen, we identify 1-carbomethoxy-5-formyl-4,6,8-trihydroxyphenazine (CMFT) to inhibit the functional interaction between the transcription factor ICBP90 (namely, UHRF1) and the MIF -794 CATT5-8 promoter microsatellite. CMFT inhibits MIF mRNA expression in a -794 CATT5-8 length-dependent manner with an IC50 of 470 nM, and preferentially reduces ICBP90-dependent MIF mRNA and protein expression in high-genotypic versus low-genotypic MIF-expressing macrophages. RNA expression analysis also showed CMFT to downregulate MIF-dependent, inflammatory gene expression with little evidence of off-target metabolic toxicity. These findings provide proof-of-concept for advancing the pharmacogenomic development of precision-based MIF inhibitors for diverse autoimmune and inflammatory conditions.

UHRF1 poly-auto-ubiquitination induced by the anti-cancer drug, thymoquinone, is involved in the DNA repair machinery recruitment

DNA methylation is one of the most important epigenetic mark involved in many physiologic cellular processes and pathologies. During mitosis, the transmission of DNA methylation patterns from a mother to the daughter cells is ensured through the action of the Ubiquitin-like, containing PHD and RING domains, 1/DNA methyltransferase 1 (UHRF1/DNMT1) tandem. UHRF1 is involved in the silencing of many tumor suppressor genes (TSGs) via mechanisms that remain largely to be deciphered. The present study investigated the role and the regulation of UHRF1 poly-ubiquitination induced by thymoquinone, a natural anti-cancer drug, known to enhance or re-activate the expression of TSGs. We found that the auto-ubiquitination of UHRF1, induced by TQ, is mediated by reactive oxygen species, and occurs following DNA damage. We demonstrated that the poly-ubiquitinated form of UHRF1 is K63-linked and can still silence the tumor suppressor gene p16INK4A/CDKN2A. We further showed that TQ-induced auto-ubiquitination is mediated via the activity of Tip60. Since this latter is known as a nuclear receptor co-factor, we investigated if the glucocorticoid receptor (GR) might be involved in the regulation of UHRF1 ubiquitination. Activation of the GR, with dexamethasone, did not influence auto-ubiquitination of UHRF1. However, we could observe that TQ induced a K48-linked poly-ubiquitination of GR, probably involved in the proteosomal degradation pathway. Mass-spectrometry analysis of FLAG-HA-tagged UHRF1 identified UHRF1 partners involved in DNA repair and showed that TQ increased their association with UHRF1, suggesting that poly-ubiquitination of UHRF1 is involved in the DNA repair process. We propose that poly-ubiquitination of UHRF1 serves as a scaffold to recruit the DNA repair machinery at DNA damage sites.

Expression of glucocorticoid receptor and HDACs in airway smooth muscle cells is associated with response to steroids in COPD

BACKGROUND

Steroid insensitivity in Chronic Obstructive Pulmonary Disease (COPD) presents a problem for controlling the chronic inflammation of the airways. The glucocorticoid receptor (GR) mediates the intracellular signaling of inhaled corticosteroids (ICS) by interacting with transcription factors and histone deacetylases (HDACs). The aim of this study was to assess if COPD patients' response to ICS in vivo, may be associated with the expression of GR, the complex of GR with transcription factors, and the expression of various HDACs in vitro.

METHODS

Primary airway smooth muscle cells (ASMC) were established from endobronchial biopsies obtained from patients with asthma (n = 10), patients with COPD (n = 10) and subjects that underwent diagnostic bronchoscopy without pathological findings and served as controls (n = 6). ASMC were also established from 18 COPD patients, 10 responders and 8 non-responders to ICS, who participated in the HISTORIC study, an investigator-initiated and driven clinical trial that proved the hypothesis that COPD patients with high ASMC in their endobronchial biopsies respond better to ICS than patients with low ASMC. Expression of GR and its isoforms GRα and GRβ and HDACs was investigated in primary ASMC in the absence or in the presence of dexamethasone (10- 8M) by western blotting. The complex formation of GR with transcription factors was assessed by co-immunoprecipitation.

RESULTS

Expression of GR and its isoform GRα but not GRβ was significantly reduced in ASMC from COPD patients as compared to controls. There were no significant differences in the expression of GR, GRα and GRβ between responders and non-responders to ICS. However, treatment with dexamethasone upregulated the expression of total GR (p = 0.004) and GRα (p = 0.005) after 30 min in responders but not in non-responders. Τhe formation of the complex GR-c-Jun was increased 60 min after treatment with dexamethasone only in responders who exhibited significantly lower expression of HDAC3 (p = 0.005) and HDAC5 (p < 0.0001) as compared to non-responders.

CONCLUSIONS

These data suggest that ASMC from COPD patients who do not respond to treatment with ICS, are characterized by reduced GR-c-Jun complex formation and increased expression of HDAC3 and HDAC5.

TRIAL REGISTRATION

ISRCTN11017699 (Registration date: 15/11/2016).

MIF contribution to progressive brain diseases

Progressive brain diseases create a huge social and economic burden on modern societies as a major cause of disability and death. Incidence of brain diseases has a significantly increasing trend and merits new therapeutic strategies. At the base of many progressive brain malfunctions is a process of unresolved, chronic inflammation. Macrophage migration inhibitory factor, MIF, is an inflammatory mediator that recently gained interest of neuro-researchers due to its varied effects on the CNS such as participation of nervous system development, neuroendocrine functions, and modulation of neuroinflammation. MIF appears to be a candidate as a new biomarker and target of novel therapeutics against numerous neurologic diseases ranging from cancer, autoimmune diseases, vascular diseases, neurodegenerative pathology to psychiatric disorders. In this review, we will focus on MIF's crucial role in neurological diseases such as multiple sclerosis (MS), Alzheimer's disease (AD) and glioblastoma (GBM).

Restraint stress promotes monobenzone-induced depigmentation in mice via the activation of glucocorticoid receptor/macrophage migration inhibitory factor signaling pathway

Psychological stress triggers onset and development of vitiligo in humans. However, the mechanism of psychological stress on vitiligo remains unclear. The study aims to investigate whether psychological stress promotes vitiligo and explore the underlying mechanism. A depigmentation mouse model induced by applying a skin-bleaching reagent monobenzone to dorsal skin and an in vitro HaCaT keratinocyte death model induced by monobenzone were employed to explore the effect of restraint stress, which mimics psychological stress, on depigmentation. The results indicated that restraint stress promoted vitiligo-related depigmentation, vacuolisation, spongiosis, CD8+ T lymphocyte infiltration, and loss of melanocytes in the skin. Restraint stress activated cutaneous NLR family containing pyrin domain protein 3 (NLRP3) inflammasome. In addition, restraint stress aggravated anxiety-like behaviors and increased levels of macrophage migration inhibitory factor (MIF) and corticosterone in the circulation, accompanied with decreasing the expression of cutaneous 8-oxoguanine DNA glycosylase (OGG1) in depigmentation mice. In vitro experiments demonstrated that activation of glucocorticoid receptor (GR) by cortisol upregulated NLRP3 expression dependent on MIF, and directly decreased the transcription of OGG1. Blockade of MIF reversed the NLRP3 signal in restraint stress-induced depigmentation mice. In conclusion, restraint stress promotes vitiligo-related depigmentation in mice via the activation of GR/MIF signaling pathway. The findings provide a theoretical basis for prevention and treatments of vitiligo with therapies of targeting GR, MIF, and OGG1.

D-dopachrome tautomerase in cardiovascular and inflammatory diseases-A new kid on the block or just another MIF?

Macrophage migration inhibitory factor (MIF) as well as its more recently described structural homolog D-dopachrome tautomerase (D-DT), now also termed MIF-2, are atypical cytokines and chemokines with key roles in host immunity. They also have an important pathogenic role in acute and chronic inflammatory conditions, cardiovascular diseases, lung diseases, adipose tissue inflammation, and cancer. Although our mechanistic understanding of MIF-2 is relatively limited compared to the extensive body of evidence available for MIF, emerging data suggests that MIF-2 is not only a functional phenocopy of MIF, but may have differential or even oppositional activities, depending on the disease and context. In this review, we summarize and discuss the similarities and differences between MIF and MIF-2, with a focus on their structures, receptors, signaling pathways, and their roles in diseases. While mainly covering the roles of the MIF homologs in cardiovascular, inflammatory, autoimmune, and metabolic diseases, we also discuss their involvement in cancer, sepsis, and chronic obstructive lung disease (COPD). A particular emphasis is laid upon potential mechanistic explanations for synergistic or cooperative activities of the MIF homologs in cancer, myocardial diseases, and COPD as opposed to emerging disparate or antagonistic activities in adipose tissue inflammation, metabolic diseases, and atherosclerosis. Lastly, we discuss potential future opportunities of jointly targeting MIF and MIF-2 in certain diseases, whereas precision targeting of only one homolog might be preferable in other conditions. Together, this article provides an update of the mechanisms and future therapeutic avenues of human MIF proteins with a focus on their emerging, surprisingly disparate activities, suggesting that MIF-2 displays a variety of activities that are distinct from those of MIF.

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.