Inhibition of Macrophage Migration Inhibitory Factor Protects against Inflammation and Matrix Deposition in Kidney Tissues after Injury

The Role of Macrophage Inhibitory Factor in TAA-Induced Liver Fibrosis in Mice: Modulatory Effects of Betaine

Macrophage inhibitory factor (MIF) is a multipotent cytokine, involved in the inflammatory response to infections or injuries. This study investigates the role of MIF in liver fibrosis and the modulating effect of betaine on MIF in thioacetamide (TAA)-induced liver fibrosis. The wild-type and knockout MIF-/- C57BL/6 mice were divided into the following groups: control; Bet group, which received betaine; MIF-/-; MIF-/-+Bet; TAA group, which received TAA; TAA+Bet; MIF-/-+TAA; and MIF-/-+TAA+Bet group. After eight weeks of treatment, liver tissue was collected for further analysis. The results revealed that TAA-treated MIF-deficient mice had elevated levels of hepatic TGF-β1 and PDGF-BB, as well as MMP-2, MMP-9, and TIMP-1 compared to TAA-treated wild-type mice. However, the administration of betaine to TAA-treated MIF-deficient mice reduced hepatic TGF-β1 and PDGF-BB levels and also the relative activities of MMP-2, MMP-9 and TIMP-1, albeit less effectively than in TAA-treated mice without MIF deficiency. Furthermore, the antifibrogenic effect of MIF was demonstrated by an increase in MMP2/TIMP1 and MMP9/TIMP1 ratios. The changes in the hepatic levels of fibrogenic factors were confirmed by a histological examination of liver tissue. Overall, the dual nature of MIF highlights its involvement in the progression of liver fibrosis. Its prooxidant and proinflammatory effects may exacerbate tissue damage and inflammation initially, but its antifibrogenic activity suggests a potential protective role against fibrosis development. The study showed that betaine modulates the antifibrogenic effects of MIF in TAA-induced liver fibrosis, by decreasing TGF-β1, PDGF-BB, MMP-2, MMP-9, TIMP-1, and the deposition of ECM (Coll1 and Coll3) in the liver.

MIF promotes cell invasion by the LRP1-uPAR interaction in pancreatic cancer cells

Introduction

Pancreatic ductal adenocarcinoma (PDAC) is characterized by high aggressiveness and a hypoxic tumour microenvironment. Macrophage migration inhibitory factor (MIF) is a hypoxia-related pleiotropic cytokine that plays important roles in cancer. However, its role in PDAC progression has not been fully elucidated.

Methods

The clinical significance of MIF and hypoxia inducible factor 1 subunit alpha (HIF1A) in PDAC was analysed using immunohistochemical staining on PDAC tissues and data from KM-Plotter database. Spatial distribution of MIF and HIF1A gene expression was visualized by spatial transcriptomics in PDAC cell xenografts. To monitor the role of MIF in PDAC cell malignancy, immunostaining, lentivirus shRNA, migration assays, flow cytometry, transcriptomics and in vivo tumorigenicity were performed.

Results

The spatial distribution of MIF and HIF1A was highly correlated and that high MIF expression was associated with poor prognosis of PDAC patients. MIF knockdown impaired cell invasion, with a decrease in the expression of urokinase-type plasminogen activator receptor (uPAR). Although PLAUR transcript was not reduced, a uPAR endocytic receptor, low-density lipoprotein receptor-related protein 1 (LRP1), was upregulated at both the mRNA and protein levels after MIF knockdown. The LRP1 antagonist RAP restored uPAR expression and invasiveness. MIF attenuated the nuclear translocation of p53, a transcriptional regulator of LRP1. Furthermore, MIF downregulation blunted the growth of PDAC cell xenografts and inhibited cell proliferation under normoxia and hypoxia. Transcriptome analysis also provided evidence for the role of MIF in cancer-associated pathways.

Discussion

We demonstrate a novel link between the two pro-invasive agents MIF and uPAR and explain how MIF increases PDAC cell invasion capability. This finding provides a basis for therapeutic intervention of MIF in PDAC progression.

Dissection of cellular and molecular mechanisms of aristolochic acid-induced hepatotoxicity via single-cell transcriptomics

Background

Aristolochic acids (AAs), a class of carcinogenic and mutagenic natural products from Aristolochia and Asarum plants, are well-known to be responsible for inducing nephrotoxicity and urothelial carcinoma. Recently, accumulating evidence suggests that exposure to AAs could also induce hepatotoxicity and even hepatocellular carcinoma, though the mechanisms are poorly defined.

Methods

Here, we aimed to dissect the underlying cellular and molecular mechanisms of aristolochic acid I (AAI)-induced hepatotoxicity by using advanced single-cell RNA sequencing (scRNA-seq) and proteomics techniques. We established the first single-cell atlas of mouse livers in response to AAI.

Results

In hepatocytes, our results indicated that AAI activated NF-κB and STAT3 signaling pathways, which may contribute to the inflammatory response and apoptosis. In liver sinusoidal endothelial cells (LSECs), AAI activated multiple oxidative stress and inflammatory associated signaling pathways and induced apoptosis. Importantly, AAI induced infiltration of cytotoxic T cells and activation of proinflammatory macrophage and neutrophil cells in the liver to produce inflammatory cytokines to aggravate inflammation.

Conclusions

Collectively, our study provides novel knowledge of AAs-induced molecular characteristics of hepatotoxicity at a single-cell level and suggests future treatment options for AAs associated hepatotoxicity.

Integrated single-cell transcriptomics and proteomics reveal cellular-specific response and microenvironment remodeling in aristolochic acid nephropathy

Aristolochic acid nephropathy (AAN) is characterized by acute proximal tubule necrosis and immune cell infiltration, contributing to the global burden of chronic kidney disease and urothelial cancer. Although the proximal tubule has been defined as the primary target of aristolochic acids I (AAI), the mechanistic underpinning of gross renal deterioration caused by AAI has not been explicitly explained, prohibiting effective therapeutic intervention. To this point, we employed integrated single-cell RNA-Seq, bulk RNA-Seq, and mass spectrometry–based proteomics to analyze the mouse kidney after acute AAI exposure. Our results reveal a dramatic reduction of proximal tubule epithelial cells, associated with apoptotic and inflammatory pathways, indicating permanent damage beyond repair. We found the enriched development pathways in other nephron segments, suggesting activation of reparative programs triggered by AAI. The divergent response may be attributed to the segment-specific distribution of organic anion channels along the nephron, including OAT1 and OAT3. Moreover, we observed dramatic activation and recruitment of cytotoxic T and macrophage M1 cells, highlighting inflammation as a principal contributor to permanent renal injury. Ligand-receptor pairing revealed that critical intercellular crosstalk underpins damage-induced activation of immune cells. These results provide potentially novel insight into the AAI-induced kidney injury and point out possible pathways for future therapeutic intervention.

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.

Sacubitril/Valsartan Improves Progression of Early Diabetic Nephropathy in Rats Through Inhibition of NLRP3 Inflammasome Pathway

PURPOSE

Diabetic nephropathy (DN), a global disease, is the leading cause of end-stage renal disease. There is a lack of specific treatment for this disease, and early intervention in disease progression is essential. In this paper, we used a rat model of early diabetic nephropathy to explore the therapeutic mechanism of sacubitril/valsartan in rats with early diabetic nephropathy.

MATERIALS AND METHODS

Rats were grouped into 1 normal group; 2. Model group (DN group): STZ (45 mg/kg/d) induced early diabetic nephropathy rats; 3. Sac group: DN rats + Sac group (orally, 60 mg/kg/d) for 6 weeks. After 6 weeks, the levels of serum albumin (ALB), glucose (GLU), creatinine (Cr), urea nitrogen (BUN) and 24-h urinary protein excretion were measured. In renal tissue homogenates, NLRP3 inflammasome, proinflammatory factors IL1-β and TNF-α, oxidative stress MDA and pro-fibrotic cytokine TGF-β1 were performed. Histological analysis of kidneys by hematoxylin and eosin (HE), PAS and Masson trichrome staining.

RESULTS

1. Sacubitril/valsartan (Sac) significantly improved renal hypertrophy, proteinuria and serum albumin levels in rats with early diabetic nephropathy (P < 0.001), and decreased GLU, Scr (P<0.001), and BUN levels (P < 0.01).2. Light microscopy of renal tissues showed glomerular hypertrophy and interstitial inflammatory cell infiltration, and mean glomerular area (MGA) and mean glomerular volume (MGV) were crucially increased in early diabetic nephropathy (P < 0.001), and the Sac group showed reduced renal pathology and improved MGA and MGV (P < 0.001).3. Kidney tissue homogenate levels of NLRP3, Caspase-1, IL1-β, TNF-α, MDA and TGF-β1 were critically, increased in DN rats (P < 0.001), and SOD was significantly decreased. All these indicators above were improved after treatment (P < 0.0001).

CONCLUSION

Nlrp3-inflammasome promote progression of diabetic nephropathy through inflammation, fibrosis and oxidative stress; sacubitril/valsartan ameliorated early diabetes-induced renal damage by inhibiting NLRP3 pathway activation.

Bone Morphogenetic Proteins (BMPs), Extracellular Matrix Metalloproteinases Inducer (EMMPRIN), and Macrophage Migration Inhibitory Factor (MIF): Usefulness in the Assessment of Tubular Dysfunction Related to Chronic Kidney Disease (CKD)

Bone morphogenetic proteins (BMP), extracellular matrix metalloproteinases inducer (EMMPRIN), and macrophage migration inhibitory factor (MIF) are known to be closely connected to renal tubule damage by experimental data; however, this has not been analyzed in children with chronic kidney disease (CKD). The aim of this study was to determine their usefulness in the assessment of CKD-related tubular dysfunction. The study group consisted of 61 children with CKD stages 1–5 and 23 controls. The serum and urine concentrations of BMP-2, BMP-6, EMMPRIN, and MIF were assessed by ELISA and their fractional excretion (FE) was calculated. The serum and urine concentrations of BMP-2, BMP-6, EMMPRIN, and MIF were significantly elevated in children with CKD vs. controls. The FE of BMP-2, FE BMP-6, and EMMPRIN increased significantly in CKD stages 1–2, but exceeded 1% in CKD stages 3–5. FE MIF became higher than in controls no sooner than in CKD 3–5, but remained below 1%. The FE values for BMP-2, BMP-6, and EMMPRIN of <1% may result from the tubular adaptive mechanisms, whereas those surpassing 1% suggest irreversible tubular damage. The analysis of serum/urinary concentrations and fractional excretion of examined parameters may allow the assessment of CKD-related tubular dysfunction.

Macrophage-derived, LRG1-enriched extracellular vesicles exacerbate aristolochic acid nephropathy in a TGFβR1-dependent manner

Aristolochic acid nephropathy (AAN) is a progressive kidney disease caused by some herbal medicines, but treatment remains ineffective. We previously found that leucine-rich α-2-glycoprotein 1 (LRG1), which regulates cellular processes, plays an important role in a kidney injury model. However, the underlying mechanism by which LRG1 regulates AAN is still unknown. In this study, we established an AAN model in vivo, a coculture system of macrophages and TECs, and a macrophage/TEC conditioned media culture model in vitro. We found that macrophage infiltration promoted injury, oxidative stress, and apoptosis in TECs. Furthermore, the role of macrophages in AAN was dependent on macrophage-derived extracellular vesicles (EVs). Importantly, we found that macrophage-derived, LRG1-enriched EVs induced TEC injury and apoptosis via a TGFβR1-dependent process. This study may help design a better therapeutic strategy to treat AAN patients.

Macrophage migration inhibitory factor (MIF): A multifaceted cytokine regulated by genetic and physiological strategies

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine encoded within a functionally polymorphic genetic locus. MIF was initially recognized as a cytokine generated by activated T cells, but in recent days it has been identified as a multipotent key cytokine secreted by many other cell types involved in immune response and physiological processes. MIF is a highly conserved 12.5 kDa secretory protein that is involved in numerous biological processes. The expression and secretion profile of MIF suggests that MIF to be ubiquitously and constitutively expressed in almost all mammalian cells and is vital for numerous physiological processes. MIF is a critical upstream mediator of host innate and adaptive immunity and survival pathways resulting in the clearance of pathogens thus playing a protective role during infectious diseases. On the other hand, MIF being an immune modulator accelerates detrimental inflammation, promotes cancer metastasis and progression, thus worsening disease conditions. Several reports demonstrated that genetic and physiological factors, including MIF gene polymorphisms, posttranslational regulations, and receptor binding control the functional activities of MIF. Taking into consideration the multi-faceted role of MIF both in physiology and pathology, we thought it is timely to review and summarize the expressional and functional regulation of MIF, its functional mechanisms associated with its beneficial and pathological roles, and MIF-targeting therapies. Thus, our review will provide an overview on how MIF is regulated, its response, and the potency of the therapies that target MIF.

Aristolochic acid I induces impairment in spermatogonial stem cell in rodents

Aristolochic acid I (AAI) is a natural bioactive substance found in plants from the Aristolochiaceae family and impairs spermatogenesis. However, whether AAI-induced spermatogenesis impairment starts at the early stages of spermatogenesis has not yet been determined. Spermatogonial stem cells (SSCs) are undifferentiated spermatogonia that balance self-renewing and differentiating divisions to maintain spermatogenesis throughout adult life and are the only adult stem cells capable of passing genes onto the next generation. The objective of this study was to investigate whether AAI impairs SSCs during the early stages of spermatogenesis. After AAI treatment, we observed looser, smaller and fewer colonies, decreased cell viability, a decreased relative cell proliferation index, and increased apoptosis in SSCs in a concentration- and/or time-dependent manner. Additionally, AAI promoted apoptosis in SSCs, which was accompanied by upregulation of caspase 3, P53 and BAX expression and downregulation of Bcl-2 expression, and suppressed autophagy, which was accompanied by upregulation of P62 expression and downregulation of ATG5 and LC3B expression, in a concentration-dependent manner. Then we found that AAI impaired spermatogenesis in rats, as identified by degeneration of the seminiferous epithelium, and increased apoptosis of testicular cells. Taken together, our findings demonstrate that AAI causes damage to SSCs and implicate apoptosis and autophagy in this process. The impairment of SSCs may contribute to AAI-induced testicular impairment. Our findings provide crucial information for the human application of botanical products containing trace amounts of AAI.

MIF inhibitor ISO-1 alleviates severe acute pancreatitis-associated acute kidney injury by suppressing the NLRP3 inflammasome signaling pathway

BACKGROUND

Acute kidney injury (AKI) is an important complication of severe acute pancreatitis (SAP) with a poor prognosis. The methyl ester of (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid (ISO-1), an inhibitor of macrophage migration inhibitory factor (MIF), has protective effects against many diseases. Our previous study confirmed MIF inhibition alleviated SAP. Here, we explored the effects of ISO-1 in an experimental mouse model of SAP-associated AKI induced by l-arginine.

METHODS

Mice were randomly divided into four treatment groups (n = 6 each): control (CON), SAP, SAP + ISO-1, and ISO-1. Histopathologic examination was used to observe damage in pancreatic and renal tissues. Biochemical and enzyme-linked immunosorbent assays (ELISA) kits were used to measure the serologic indicators amylase, lipase, creatinine, uric acid, interleukin (IL)-6, and tumor necrosis factor (TNF)-α. Immunohistochemistry was used to detect protein expression of NLRP3, ASC and caspase-1, and the infiltration of myeloperoxidase (MPO)-positive neutrophils in kidney tissue. Western blotting was used to detect NLRP3, ASC and caspase-1 and IL-1β protein expression, and real-time PCR was used to measure MIF, IL-6, TNF-α, IL-1β and IL-18 mRNA levels in kidney tissue.

RESULTS

ISO-1 treatment alleviated pathological damage in pancreatic and renal tissues, and reduced the serum levels of amylase, lipase, creatinine, uric acid, IL-6 and TNF-α. ISO-1 also reduced protein expression of NLRP3, ASC, caspase-1 and IL-1β, mRNA expression of MIF, IL-6, TNF-α, IL-1β and IL-18, and the infiltration of MPO-positive neutrophils in kidney tissue.

CONCLUSION

ISO-1 has a protective effect against experimental SAP-associated AKI. And the mechanism may be associated with ISO-1 inhibiting NLRP3 inflammasome signaling pathway.

Anti-Inflammatory, Antioxidant, and Antifibrotic Effects of Kefir Peptides on Salt-Induced Renal Vascular Damage and Dysfunction in Aged Stroke-Prone Spontaneously Hypertensive Rats

The increased prevalence of renal dysfunction and chronic kidney disease (CKD) and the high costs and poor outcomes of treatment are a significant health issue. The consequence of chronic high blood pressure is the increased prevalence of target organ end-stage renal disease, which has been proven to be a strong independent risk factor for adverse cardiovascular disease. A previous study showed that kefir products have anti-inflammatory and anti-hypertensive activities and immunological modulation functions. However, no data regarding the beneficial effects of kefir peptides (KPs) on salt-induced renal damage or related kidney diseases are available. In this study, KPs were orally administered to aged salt-induced stroke-prone spontaneously hypertensive (SHRSP) rats, and the effects of KPs against inflammation and oxidative stress and their ability to protect against renal dysfunction were evaluated. Fifty-five-week-old SHRSP rats under induction with 1% NaCl in drinking water for 4 weeks showed multiple renal injuries with increased renal inflammation, fibrosis, oxidative stress, tubular atrophy, and glomerulosclerosis. In contrast, oral gavage with KPs reduced the urine protein to creatinine (UPC) ratio, the fractional excretion of electrolytes (FeNa and FeCl), extracellular matrix deposition, and the interstitial fibrotic α-smooth muscle actin (α-SMA) levels in salt-induced SHRSP rats. The renal infiltration of inflammatory cells; the release of monocyte chemoattractant protein-1 (MCP-1), vascular cell adhesion molecule-1 (VCAM-1), endothelin-1 (ET-1), and the cytokine nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) and transforming growth factor-β (TGF-β); the reactive oxygen species (ROS) levels; and histopathological lesions were also decreased in salt-induced SHRSP rats. Furthermore, KP treatment significantly increased the renal superoxide dismutase (SOD) activity and the glomerular filtration rate (GFR), which exerted potent protection against salt-induced chronic kidney disease in SHRSP rats. The results of this study suggest that KPs ameliorate salt-induced renal damage, tubular atrophy, and glomerular dysfunction through anti-inflammatory, antioxidative stress, and antifibrotic activities, and might be a promising protective agent against high salt-induced renovascular-related diseases.

Macrophage migration inhibitory factor promotes renal injury induced by ischemic reperfusion

Macrophage migration inhibitory factor (MIF) is pleiotropic cytokine that has multiple effects in many inflammatory and immune diseases. This study reveals a potential role of MIF in acute kidney injury (AKI) in patients and in kidney ischemic reperfusion injury (IRI) mouse model in MIF wild‐type (WT) and MIF knockout (KO) mice. Clinically, plasma and urinary MIF levels were largely elevated at the onset of AKI, declined to normal levels when AKI was resolved and correlated tightly with serum creatinine independent of disease causes. Experimentally, MIF levels in plasma and urine were rapidly elevated after IRI‐AKI and associated with the elevation of serum creatinine and the severity of tubular necrosis, which were suppressed in MIF KO mice. It was possible that MIF may mediate AKI via CD74/TLR4‐NF‐κB signalling as mice lacking MIF were protected from AKI by largely suppressing CD74/TLR‐4‐NF‐κB associated renal inflammation, including the expression of MCP‐1, TNF‐α, IL‐1β, IL‐6, iNOS, CXCL15(IL‐8 in human) and infiltration of macrophages, neutrophil, and T cells. In conclusion, our study suggests that MIF may be pathogenic in AKI and levels of plasma and urinary MIF may correlate with the progression and regression of AKI.

miR-152 Attenuates the Severity of Lupus Nephritis Through the Downregulation of Macrophage Migration Inhibitory Factor (MIF)-Induced Expression of COL1A1

Background: The role of miR-152 in lupus nephritis has not been elucidated. The aim of this study was to investigate the role of miR-152 in the pathogenesis of lupus nephritis (LN).

Methods: miR-152 expression was detected using RT-PCR in LN tissue and normal controls. The miR-152 expression was compared with clinical parameters such as 24 h urine protein excretion level, serum creatinine, and serum complement level and SLEDAI score. The function of miR-152 was examined using human renal proximal tubular epithelial cells (HRPTE). miR-152 mimics and inhibitors were transfected to HRPTEs to ascertain the effects of miR-152.

Results: miR-152 expression was downregulated in LN tissue. There was an inverse correlation between miR-152 expression in LN tissue and clinical parameters like 24 h urine protein excretion levels and serum creatinine, but not serum complement levels or SLEDAI. Further analysis showed that macrophage migration inhibitory factor (MIF) was a direct target of miR-152. Downregulation of MIF through complementary binding of miR-152 inhibited the renal expression of COL1A1.

Conclusion: miR-152 expression was tapered in LN tissue and miR-152 expression was inversely correlated with chronicity index (CI), serum creatinine and severity of proteinuria. miR-152 may attenuate the severity of LN through the downregulation of MIF-induced expression of COL1A1. These findings suggest that miR-152 may be a potential target for the treatment of LN.

Macrophage Migration Inhibitory Factor (MIF) Inhibition in a Murine Model of Bleomycin-Induced Pulmonary Fibrosis

Background: Pulmonary hypertension (PH) is a common complication of idiopathic pulmonary fibrosis (IPF) that significantly contributes to morbidity and mortality. Macrophage migration inhibitory factor (MIF) is a critical factor in vascular remodeling of the pulmonary circulation. Objectives: We tested the effects of two small molecules targeting MIF on bleomycin (BLM)-induced collagen deposition, PH, and vascular remodeling in mouse lungs. Methods: We examined the distribution pattern of MIF, CD74, and CXCR4 in the lungs of patients with IPF-PH and the lungs of BLM-injected mice. Then, treatments were realized with (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1) and N-(3-hydroxy-4-fluorobenzyl)-5 trifluoromethylbenzoxazol-2-thione 31 (20 mg/kg/day per os for 3 weeks) started 24 h after an intratracheal BLM administration. Results: More intense immunoreactivity was noted for MIF, CD74, and CXCR4 in lungs from IPF-PH patients and BLM-injected mice. Furthermore, we found that treatments of BLM-injected mice with ISO-1 or compound 31 attenuated lung collagen deposition and right ventricular systolic pressure increase. Additionally, reduced pulmonary inflammatory infiltration and pulmonary arterial muscularization were observed in the lungs of BLM-injected mice treated with ISO-1 or compound 31. Conclusions: Treatments with ISO-1 or compound 31 attenuates BLM-induced inflammation and fibrosis in lung, and prevents PH development in mice, suggesting that MIF is an important factor for IPF-PH development.

Macrophage migration inhibitory factor contributes to the pathogenesis of benign lymphoepithelial lesion of the lacrimal gland

Background

Benign Lymphoepithelial Lesion (BLEL) is a rare disease observed in the adult population. Despite the growing numbers of people suffering from BLEL, the etiology and mechanisms underlying its pathogenesis remain unknown.

Methods

In the present study, we used gene and cytokines expression profiling, western blot and immunohistochemistry to get further insight into the cellular and molecular mechanisms involved in the pathogenesis of BLEL of the lacrimal gland.

Results

The results showed that Macrophage Migration Inhibitory Factor (MIF) was the most highly expressed cytokine in BLEL, and its expression positively correlated with the expression of Th2 and Th17 cells cytokines. MIF was found to regulate biological functions and pathways involved in BLEL pathogenesis, such as proliferation, resistance to apoptosis, MAPK and PI3K/Akt pathways. We also found that MIF promotes fibrosis in BLEL by inducing BLEL fibroblast differentiation into myofibroblasts as well as the synthesis and the deposit of extracellular matrix in BLEL tissues.

Conclusions

Our findings demonstrate the contribution of MIF to the pathogenesis of BLEL of the lacrimal gland and suggested MIF as a promising therapeutic target for its treatment.

Electronic supplementary material

The online version of this article (10.1186/s12964-018-0284-4) contains supplementary material, which is available to authorized users.

Blocking Macrophage Migration Inhibitory Factor Protects Against Cisplatin-Induced Acute Kidney Injury in Mice

Macrophage migration inhibitory factor (MIF) is elevated in patients with acute kidney injury (AKI) and is suggested as a potential predictor for renal replacement therapy in AKI. In this study, we found that MIF also plays a pathogenic role and is a therapeutic target for AKI. In a cisplatin-induced AKI mouse model, elevated plasma MIF correlated with increased serum creatinine and the severity of renal inflammation and tubular necrosis, whereas deletion of MIF protected the kidney from cisplatin-induced AKI by largely improving renal functional and histological injury, and suppressing renal inflammation including upregulation of cytokines such as interleukin (IL)-1β, tumor necrosis factor-alpha (TNF-α), IL-6, inducible nitric oxide synthase (iNOS), MCP-1, IL-8, and infiltration of macrophages, neutrophils, and T cells. We next developed a novel therapeutic strategy for AKI by blocking the endogenous MIF with an MIF inhibitor, ribosomal protein S19 (RPS19). Similar to the MIF-knockout mice, treatment with RPS19, but not the mutant RPS19, suppressed cisplatin-induced AKI. Mechanistically, we found that both genetic knockout and pharmacological inhibition of MIF protected against AKI by inactivating the CD74-nuclear factor κB (NF-κB) signaling. In conclusion, MIF is pathogenic in cisplatin-induced AKI. Targeting MIF with an MIF inhibitor RPS19 could be a promising therapeutic potential for AKI.

Mesenchymal stem cells alleviate acute kidney injury by down-regulating C5a/C5aR pathway activation

BACKGROUND

Acute kidney injury (AKI) leads to serious renal damage, and early inhibition of inflammation is necessary for its treatment. C5a/C5aR signaling activation promotes inflammatory response in tissue injury. Anti-inflammatory activity of mesenchymal stem cells (MSCs) makes it possible to alleviate AKI by controlling the C5a/C5aR signaling activation.

METHODS

Ischemia reperfusion (I/R)-induced AKI models in wild-type and C5aR KO mice were used. In addition, human bone marrow MSCs (hBM-MSCs) or C5aR antagonist were injected in this model. All animals were killed at 72 h after reperfusion. In vitro, the LPS-activated macrophage line RAW264.7 cells were co-cultured with or without hBM-MSCs in the presence of recombinant C5a or not for indicated time points. After that, C5aR expression, the inflammatory factor production, and NF-κB translocation in RAW264.7 cells were measured.

RESULTS

hBM-MSC treatment and C5a/C5aR signaling blockade or C5aR-deficiency exhibited similar attenuated effects on I/R-induced AKI, macrophages infiltration, and the pro-inflammatory cytokines TNF-α and IL-1β expression in renal tissues in mice. Moreover, hBM-MSC administration led to a significant reduction in C5a levels in serum and C5aR expression in the kidney tissues in mice after I/R. In vitro, upon co-culture with hBM-MSCs, both C5aR expression and the secretion of pro-inflammatory factors TNF-α, IL-6, and nitric oxide in LPS-activated macrophages were markedly reduced. Accordingly, recombinant complement C5a accelerated LPS-induced NF-κB translocation and pro-inflammatory factors expression in macrophages, but the addition of hBM-MSCs reversed these C5a-induced effects.

CONCLUSIONS

The present study indicates that hBM-MSCs alleviate AKI via suppressing C5a/C5aR-NF-κB pathway activation.

Macrophage migration inhibitory factor antagonist (S,R)3‑(4‑hydroxyphenyl)‑4,5‑dihydro‑5‑isoxazole acetic acid methyl ester attenuates inflammation and lung injury in rats with acute pancreatitis in pregnancy

Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine involved in many acute and chronic inflammatory diseases. However, its role in acute lung injury associated with acute pancreatitis in pregnancy (APIP) has not yet been elucidated. The present study was undertaken to clarify the effect and potential mechanism of MIF antagonist (S,R)3‑(4‑hydroxyphenyl)‑4,5‑dihydro‑5‑isoxazole acetic acid methyl ester (ISO‑1) in the development of acute lung injury in rats with APIP. Eighteen late‑gestation SD rats were randomly assigned to three groups: Sham operation (SO) group, APIP group, and ISO‑1 group. All the rats were sacrificed 6 h after modeling. The severity of pancreatitis was evaluated by serum amylase (AMY), lipase (LIPA), tumor necrosis factor (TNF)‑α, interleukin (IL)‑1β and IL‑6 and assessing the histopathological score. Lung injury was determined by performing histology and inflammatory cell infiltration investigations. Western blot analysis was used to detect the protein expression of MIF, phosphorylated and total P38 and nuclear factor‑κB (NF‑κB) protein in lungs. The results showed that MIF was upregulated in the lung of APIP rats. Compared with APIP group, the intervention of ISO‑1 alleviated the pathological injury of the pancreas and lungs, decreased serum AMY and LIPA, attenuated serum concentrations of TNF‑α, IL‑1β, and IL‑6, reduced the number of MPO‑positive cells in the lung and inhibited the activation of P38MAPK and NF‑κB. These results suggest that MIF is activated in lung injury induced by APIP. Furhtermore, the present findings indicate that the MIF antagonist ISO‑1 has a protective effect on lung injury and inflammation, which may be associated with deactivating the P38MAPK and NF‑κB signaling pathway.

Fetal liver injury ameliorated by migration inhibitory factor inhibition in a rat model of acute pancreatitis in pregnancy

AIM

This study was designed to investigate and assess fetal liver injury in a rat model of acute pancreatitis in pregnancy (APIP) as well as its possible mechanisms and potential therapeutic targets.

METHODS

The APIP model was induced by sodium taurocholate in Sprague-Dawley rats during the third trimester. ISO-1, a macrophage migration inhibitory factor (MIF) antagonist, was given before the induction of APIP. In addition, sham-operated rats at later gestation were set as controls. Histological changes in the fetal liver and maternal pancreas were assessed. Amylase and lipase activity as well as the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β were examined. The expression of MIF in fetal liver was determined by immunochemistry and the expression of NF-κB, IκBα, high mobility group box-1 protein (HMGB1), TNF-α, and IL-1β in fetal liver was determined by Western blot analysis. Ultrastructures of hepatic cells in fetal rats were observed under transmission electron microscopy.

RESULTS

ISO-1 ameliorated the following: (i) pathological injuries in maternal pancreas and fetal liver; (ii) levels of TNF-α and IL-1β in maternal serum; and (iii) levels of MIF, myeloperoxidase, NF-κB, HMGB1, TNF-α, and IL-1β in fetal liver.

CONCLUSION

Pathological damage and an inflammatory response in fetal liver were induced by APIP, and MIF inhibition ameliorated fetal liver injury by inhibiting the inflammatory cascade.