HSD17B13 liquid-liquid phase separation promotes leukocyte adhesion in chronic liver inflammation.

The rs72613567:TA polymorphism in 17-beta hydroxysteroid dehydrogenase 13 (HSD17B13) has been found to reduce the progression from steatosis to nonalcoholic steatohepatitis. In this study, we sought to define the pathogenic role of HSD17B13 in triggering liver inflammation. Here we find that HSD17B13 forms liquid-liquid phase separation (LLPS) around lipid droplets in the livers of nonalcoholic steatohepatitis patients. The dimerization of HSD17B13 supports the LLPS formation and promotes its enzymatic function. HSD17B13 LLPS increases the biosynthesis of platelet activating factor (PAF), which in turn promotes fibrinogen synthesis and leukocyte adhesion. Blockade of PAFR or STAT3 pathway inhibited the fibrinogen synthesis and leukocyte adhesion. Importantly, adeno-associated viral-mediated xeno-expression of human HSD17B13 exacerbated western diet/carbon tetrachloride-induced liver inflammation in Hsd17b13-/- mice. In conclusion, our results suggest that HSD17B13 LLPS triggers liver inflammation by promoting PAF-mediated leukocyte adhesion, and targeting HSD17B13 phase transition could be a promising therapeutic approach for treating hepatic inflammation in chronic liver disease.

Mitochondrial folate metabolism-mediated α-linolenic acid exhaustion masks liver fibrosis resolution.

Sustainable TGF-ß1 signaling drives organ fibrogenesis. However, the cellular adaptation to maintain TGF-ß1 signaling remains unclear. In this study, we revealed that dietary folate restriction promoted the resolution of liver fibrosis in mice with nonalcoholic steatohepatitis. In activated hepatic stellate cells, folate shifted toward mitochondrial metabolism to sustain TGF-ß1 signaling. Mechanistically, nontargeted metabolomics screening identified that α-linolenic acid (ALA) is exhausted by mitochondrial folate metabolism in activated hepatic stellate cells. Knocking down serine hydroxymethyltransferase 2 increases the bioconversion of ALA to docosahexaenoic acid, which inhibits TGF-ß1 signaling. Finally, blocking mitochondrial folate metabolism promoted liver fibrosis resolution in nonalcoholic steatohepatitis mice. In conclusion, mitochondrial folate metabolism/ALA exhaustion/TGF-ßR1 reproduction is a feedforward signaling to sustain profibrotic TGF-ß1 signaling, and targeting mitochondrial folate metabolism is a promising strategy to enforce liver fibrosis resolution.

Neuron stem cell NLRP6 sustains hippocampal neurogenesis to resist stress-induced depression.

Neurogenesis decline in hippocampal dentate gyrus (DG) participates in stress-induced depressive-like behaviors, but the underlying mechanism remains poorly understood. Here, we observed low-expression of NOD-like receptor family pyrin domain containing 6 (NLRP6) in hippocampus of stress-stimulated mice, being consistent with high corticosterone level. NLRP6 was found to be abundantly expressed in neural stem cells (NSCs) of DG. Both Nlrp6 knockout (Nlrp6-/-) and NSC-conditional Nlrp6 knockout (Nlrp6CKO) mice were susceptible to stress, being more likely to develop depressive-like behaviors. Interestingly, NLRP6 was required for NSC proliferation in sustaining hippocampal neurogenesis and reinforcing stress resilience during growing up. Nlrp6 deficiency promoted esophageal cancer-related gene 4 (ECRG4) expression and caused mitochondrial dysfunction. Corticosterone as a stress factor significantly down-regulated NLRP6 expression, damaged mitochondrial function and suppressed cell proliferation in NSCs, which were blocked by Nlrp6 overexpression. ECRG4 knockdown reversed corticosterone-induced NSC mitochondrial function and cell proliferation disorders. Pioglitazone, a well-known clinical drug, up-regulated NLRP6 expression to inhibit ECRG4 expression in its protection against corticosterone-induced NSC mitochondrial dysfunction and proliferation restriction. In conclusion, this study demonstrates that NLRP6 is essential to maintain mitochondrial homeostasis and proliferation in NSCs, and identifies NLRP6 as a promising therapeutic target for hippocampal neurogenesis decline linked to depression.

CXCL10-armed oncolytic adenovirus promotes tumor-infiltrating T-cell chemotaxis to enhance anti-PD-1 therapy.

Resistance remains an obstacle to anti-programmed cell death protein 1 (PD-1) therapy in human cancer. One critical resistance mechanism is the lack of T cell chemotaxis in the tumor microenvironment (TME). CXCL10-CXCR3 signaling is required for T cell tumor infiltration and tumor immunotherapy. Oncolytic viruses (OVs), including oncolytic adenoviruses (AdVs), induce effective T cell immunity and tumor infiltration. Thus, arming OV with CXCL10 would be an attractive strategy to overcome resistance to anti-PD1 therapy. Here, we successfully constructed a novel recombinant oncolytic adenovirus encoding murine CXCL10, named Adv-CXCL10. Through intratumoural injection, the continuous expression of the functional chemokine CXCL10 in the TME is realized to recruit more CXCR3+ T cells into the TME to kill tumor cells, and the recombinant adenovirus shows great power to 'fire up' the TME and enhance the antitumour efficiency of PD-1 antibodies.

Rational design, synthesis and biological evaluation of dual PARP-1/2 and TNKS1/2 inhibitors for cancer therapy.

Poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors are the first and most successful drugs designed to exploit the concept of synthetic lethality (SL) between PARP-1 and BRCA1/2, which provides a novel strategy for tumor treatment. However, narrowed indications and resistance to PARP-1 inhibitors have hampered their further clinical application. Inducing "BRCAness" by targeting other targets, which will directly or indirectly disturb the homologous recombination (HR) repair pathway of double-strand DNA breaks (DSBs), is a promising strategy for expanding the clinical application of PARP-1 inhibitors and overcoming resistance to these inhibitors. Tankyrase1/2 (TNKS1/2) are involved in the nonhomologous end-joining (NHEJ) DNA repair pathway by regulating Wnt/ß-catenin signaling. TNKS1/2 can also induce a "BRCAness" phenotype by regulating Wnt signaling, which increases the sensitivity of tumor cells with BRCA proficiency to PARP-1 inhibitors. These results suggest that cotargeting PARP1/2 and TNKS1/2 not only exerts a synergistic effect in the treatment of tumors but also provides a novel strategy for expanding the clinical application of PARP-1 inhibitors and overcoming resistance to PARP-1 inhibitors. Therefore, a series of dual PARP-1/2 and TNKS1/2 inhibitors were rationally designed, synthesized, and evaluated for their pharmacological properties. Among these candidates, compound I-9 showed excellent inhibitory activity as it inhibited PARP-1/2 and TNKS1/2 with IC50 values of 0.25 nM, 1.2 nM, 13.5 nM and 4.15 nM, respectively. I-9 exhibited favorable synergistic antitumor efficacy in both BRCA-mutant and BRCA-wild-type cancer lines. Moreover, I-9 exerted prominent dose-dependent antitumor activity in an HCT116 cell-derived xenograft model and was significantly more efficacious than olaparib and E7449. Overall, the present study indicated that I-9, a dual PARP-1/2 and TNKS1/2 inhibitor, is a novel and promising agent for cancer therapy.

Small molecule targeting CELF1 RNA-binding activity to control HSC activation and liver fibrosis.

CUGBP Elav-like family member 1 (CELF1), an RNA-binding protein (RBP), plays important roles in the pathogenesis of diseases such as myotonic dystrophy, liver fibrosis and cancers. However, targeting CELF1 is still a challenge, as RBPs are considered largely undruggable. Here, we discovered that compound 27 disrupted CELF1-RNA binding via structure-based virtual screening and biochemical assays. Compound 27 binds directly to CELF1 and competes with RNA for binding to CELF1. Compound 27 promotes IFN-γ secretion and suppresses TGF-ß1-induced hepatic stellate cell (HSC) activation by inhibiting CELF1-mediated IFN-γ mRNA decay. In vivo, compound 27 attenuates CCl4-induced murine liver fibrosis. Furthermore, the structure-activity relationship analysis was performed and compound 841, a derivative of compound 27, was identified as a selective CELF1 inhibitor. In conclusion, targeting CELF1 RNA-binding activity with small molecules was achieved, which provides a novel strategy for treating liver fibrosis and other CELF1-mediated diseases.

Targeted Isolation of a Cytotoxic Cyclic Hexadepsipeptide from the Mesophotic Zone Sponge-Associated Fungus Cymostachys sp. NBUF082.

LC-MS/MS-based molecular networking facilitated the targeted isolation of a new cyclic hexadepsipeptide, cymodepsipeptide (1), and two known analogues, RF-2691A (2) and RF-2691B (3), from the fungus Cymostachys sp. NBUF082 that was derived from a mesophotic zone Aaptos sponge collected near Apo Island. The constitution and configuration of 1 was elucidated through 1D and 2D NMR-spectroscopy, high resolution mass-spectrometry, and chemical degradations including Marfey's analysis and chiral HPLC. It was observed that 1 was moderately cytotoxic against CCRF-CEM human acute lymphocytic leukemia cells in vitro with the IC50 value of 9.2 ± 1.1 µM.

CXCR6 is required for antitumor efficacy of intratumoral CD8+ T cell.

BACKGROUND: Increasing infiltration of CD8+ T cells within tumor tissue predicts a better prognosis and is essential for response to checkpoint blocking therapy. Furthermore, current clinical protocols use unfractioned T cell populations as the starting point for transduction of chimeric antigen receptors (CARs)-modified T cells, but the optimal T cell subtype of CAR-modified T cells remains unclear. Thus, accurately identifying a group of cytotoxic T lymphocytes with high antitumor efficacy is imperative. Inspired by the theory of yin and yang, we explored a subset of CD8+ T cell in cancer with the same phenotypic characteristics as highly activated inflammatory T cells in autoimmune diseases. METHODS: Combination of single-cell RNA sequencing, general transcriptome sequencing data and multiparametric cytometric techniques allowed us to map CXCR6 expression on specific cell type and tissue. We applied Cxcr6-/- mice, immune checkpoint therapies and bone marrow chimeras to identify the function of CXCR6+CD8+ T cells. Transgenic Cxcr6-/- OT-I mice were employed to explore the functional role of CXCR6 in antigen-specific antitumor response. RESULTS: We identified that CXCR6 was exclusively expressed on intratumoral CD8+ T cell. CXCR6+CD8+ T cells were more immunocompetent, and chimeras with specific deficiency on CD8+ T cells showed weaker antitumor activity. In addition, Cxcr6-/- mice could not respond to anti-PD-1 treatment effectively. High tumor expression of CXCR6 was not mainly caused by ligand-receptor chemotaxis of CXCL16/CXCR6 but induced by tumor tissue self. Induced CXCR6+CD8+ T cells possessed tumor antigen specificity and could enhance the effect of anti-PD-1 blockade to retard tumor progression. CONCLUSIONS: This study may contribute to the rational design of combined immunotherapy. Alternatively, CXCR6 may be used as a biomarker for effective CD8+ T cell state before adoptive cell therapy, providing a basis for tumor immunotherapy.

Fraxinellone alleviates kidney fibrosis by inhibiting CUG-binding protein 1-mediated fibroblast activation.

Chronic Kidney Disease (CKD) is a serious threat to human health. In addition, kidney fibrosis is a key pathogenic intermediate for the progression of CDK. Moreover, excessive activation of fibroblasts is key to the development of kidney fibrosis and this process is difficult to control. Notably, fraxinellone is a natural compound isolated from Dictamnus dasycarpus and has a variety of pharmacological activities, including hepatoprotective, anti-inflammatory and anti-cancer effects. However, the effect of fraxinellone on kidney fibrosis is largely unknown. The present study showed that fraxinellone could alleviate folic acid-induced kidney fibrosis in mice in a dose dependent manner. Additionally, the results revealed that fraxinellone could effectively down-regulate the expression of CUGBP1, which was highly up-regulated in human and murine fibrotic renal tissues. Furthermore, expression of CUGBP1 was selectively induced by the Transforming Growth Factor-beta (TGF-ß) through p38 and JNK signaling in kidney fibroblasts. On the other hand, downregulating the expression of CUGBP1 significantly inhibited the activation of kidney fibroblasts. In conclusion, these findings demonstrated that fraxinellone might be a new drug candidate and CUGBP1 could be a promising target for the treatment of kidney fibrosis.

Cytotoxic Polyketide Metabolites from a Marine Mesophotic Zone Chalinidae Sponge-Associated Fungus Pleosporales sp. NBUF144.

Two new polyketide natural products, globosuxanthone F (1), and 2'-hydroxy bisdechlorogeodin (2), were isolated from the fungus Pleosporales sp. NBUF144, which was derived from a 62 m deep Chalinidae family sponge together with four known metabolites, 3,4-dihydroglobosuxanthone A (3), 8-hydroxy-3-methylxanthone-1-carboxylate (4), crosphaeropsone C (5), and 4-megastigmen-3,9-dione (6). The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D NMR and high-resolution electrospray ionization mass spectra (HRESIMS) data. The absolute configuration of 1 was further established by single-crystal X-ray diffraction studies. Compounds 1-5 were evaluated for cytotoxicity towards CCRF-CEM human acute lymphatic leukemia cells, and it was found that 1 had an IC50 value of 0.46 µM.

Discovery of Cymopolyphenols A-F From a Marine Mesophotic Zone Aaptos Sponge-Associated Fungus Cymostachys sp. NBUF082.

Mesophotic coral ecosystems (MCEs) have complex but understudied biodiversity, especially for natural products discovery. Untargeted metabolomics research on 80 extracts prepared from marine sponge-associated fungi, half from shallow reefs (<30 m) and half from MCEs (30-150 m), facilitated prioritization for further study a Cymostachys fungus from a 103 m deep Aaptos sponge. LC-MS target-directed isolation yielded a series of new compounds, cymopolyphenols A-F (1-6), and two known phenylspirodrimanes, F1839-I (7) and stachybotrylactone (8). This is the first report of natural products from the recently described genus, Cymostachys. Compounds 1-6 and 8 contain a dihydroisobenzofuran moiety, and 4-6 are low-order polymers of 1 with novel scaffolds. The structures of the compounds were established by spectroscopic and spectrometric data interpretation, with further support from X-ray crystallography studies of 3 and 4. Compound 3 undergoes facile racemization in solution and was found to crystalize as a racemic mixture. Compound 5 was also obtained in racemic form, and after chiral chromatography, both separated enantiomers racemized in solution by a presumed keto-enol tautomerization. Compounds 1 and 3-6 were found to be weakly antimicrobial (MIC 16-64 µg/ml) in vitro against several Gram-positive and Gram-negative human or aquatic pathogens, compound 5 was shown to chelate iron in vitro at 10 µM, and 8 activated plant disease resistance in vivo in a transgenic model organism.

Landscape of SARS-CoV-2 spike protein-interacting cells in human tissues.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic. However, the mechanism of tissue tropism of SARS-CoV-2 remains unclear. Here, recombinant receptor-binding subdomain 1 of spike protein of SARS-CoV-2 (RBD-SD1) was used as a probe to investigate the potential tropism of SARS-CoV-2 in thirty-three types of normal human tissues. RBD-SD1 probe was observed to interact with cells in reported SARS-CoV-2 infected organs. Interestingly, the RBD-SD1 probe strongly interacted with bone marrow cells in an angiotensin-converting enzyme 2 (ACE2)-independent manner. In addition, SARS-CoV-2 induced the ACE2 mRNA expression in human primary bone marrow cells, suggesting human bone marrow cells may be sensitive to SARS-CoV-2 infection. Therefore, human bone marrow cells could be strongly infected by SARS-CoV-2, which may play an important role in the pathogenesis of COVID-19. These findings provide a deeper understanding of SARS-CoV-2 infection routes, thus contributing to the treatment of COVID-19.

Mulberroside A repairs high fructose diet-induced damage of intestinal epithelial and blood-brain barriers in mice: A potential for preventing hippocampal neuroinflammatory injury.

Our previous studies showed that high fructose diet (HFrD)-driven gut dysbiosis caused fecal short-chain fatty acids (SCFAs) reduction and intestinal epithelial barrier (IEB) damage in mice, which might play an important role in hippocampal neuroinflammatory injury. Mulberroside A is reported to have neuroprotective effects in animal experiments, while the underlying mechanisms are not yet fully elucidated. Here, we investigated whether and how mulberroside A prevented HFrD-induced neuroinflammatory injury. HFrD-fed mice were treated orally with mulberroside A (20 and 40 mg/kg) for 8 weeks. Mulberroside A was found to inhibit hippocampal neuroinflammation and neurogenesis reduction in HFrD-fed mice. It reshaped gut dysbiosis, increased fecal and serum SCFAs contents, reactivated signaling of the colonic NLR family, pyrin domain containing 6 (NLRP6) inflammasome, and up-regulated Muc2 expression to prevent IEB damage, as well as subsequently, reduced serum endotoxin levels in this animal model. Additionally, mulberroside A inhibited oxidative stress in colon of HFrD-fed mice and hydrogen peroxide (H2 O2 )-stimulated Caco-2 cells. Blood-brain barrier (BBB) structure defects were also observed in HFrD-driven hippocampal neuroinflammatory injury of mice. Interestingly, mulberroside A maintained astrocyte morphology and up-regulated tight junction proteins to repair BBB structure defects in hippocampus dentate gyrus (DG). Our results demonstrated that mulberroside A was capable of preventing HFrD-induced damage of IEB and BBB in mice, which might contribute to the suppression of hippocampal neuroinflammatory injury.

Possibility of magnesium supplementation for supportive treatment in patients with COVID-19.

Magnesium as an enzymatic activator is essential for various physiological functions such as cell cycle, metabolic regulation, muscle contraction, and vasomotor tone. A growing body of evidence supports that magnesium supplementation (mainly magnesium sulfate and magnesium oxide) prevents or treats various types of disorders or diseases related to respiratory system, reproductive system, nervous system, digestive system, and cardiovascular system as well as kidney injury, diabetes and cancer. The ongoing pandemic coronavirus disease 19 (COVID-19) characterized by respiratory tract symptoms with different degrees of important organ and tissue damages has attracted global attention. Particularly, effective drugs are still lacking in the COVID-19 therapy. In this review, we find and summarize the effectiveness of magnesium supplementation on the disorders or diseases, and provide a reference to the possibility of magnesium supplementation for supportive treatment in patients with COVID-19.

Role of CXCR3 signaling in response to anti-PD-1 therapy.

BACKGROUND: Tumor mutations and tumor microenvironment are associated with resistance to cancer immunotherapies. However, peripheral T cell in effective anti-programmed death 1 (PD-1) antibody treatment is poorly understood. METHODS: Mass spectrometry and conventional flow cytometry were used to investigate peripheral blood cells isolated from patients. Furthermore, melanoma mouse model was performed to assess the role of CXCR3 signaling in anti-PD-1 antibody treatment. FINDINGS: We revealed a marked increase in the percentage of CXCR3+ T cells in the blood of cancer patients after the first pembrolizumab infusion. This percentage decreased after the second infusion in responsive patients, whereas a sustained high percentage of CXCR3+ T cells was observed in patients with progressive disease. A low percentage of CXCR3+ T cells presented in patients with stable disease or a partial response was confirmed by conventional flow cytometry. Intriguingly, blockade of CXCR3 signaling exacerbated tumor growth in mice. Intratumoral injection with recombinant CXCL9/10 plus intraperitoneal injection of anti-PD1 antibody inhibited the tumor growth in mice. INTERPRETATION: The dynamic changes in CXCR3+ T cells in blood may be a prognostic factor in anti-PD-1 immunotherapy, and promotion of CXCR3-mediated signaling may be beneficial to the anti-PD-1 therapy. FUND: This work was supported by the National Natural Science Foundation of China (Nos. 81722047, 81871944, 81670553, 81874317, 81572389, 81730100) and Jiangsu province key medical talents (Nos. ZDRCA2016026), The "Deng Feng" Distinguished Scholars Program, National Science & Technology Major Project "Key New Drug Creation and Manufacturing Program", China (Number: 2018ZX09201002), and the Fundamental Research Funds for the Central Universities (020814380117).

Seselin ameliorates inflammation via targeting Jak2 to suppress the proinflammatory phenotype of macrophages.

BACKGROUND AND PURPOSE: Sepsis is a serious clinical condition with a high mortality rate. Anti inflammatory agents have been found to be beneficial for the treatment of sepsis. Here, we have evaluated the anti-inflammatory activity of seselin in models of sepsis and investigated the underlying molecular mechanism(s). EXPERIMENTAL APPROACH: In vivo therapeutic effects of seselin was evaluated in two models of sepsis, caecal ligation and puncture or injection of LPS, in C57BL/6 mice. In vitro, anti-inflammatory activity of seselin was assessed with macrophages stimulated with LPS and IFN-γ. Anti inflammatory actions were analysed with immunohistochemical methods, ELISA and Western blotting. Flow cytometry was used to assess markers of macrophage phenotype (pro- or anti-inflammatory). Other methods used included co-immunoprecipitation, cellular thermal shift assay and molecular docking. KEY RESULTS: In vivo, seselin clearly ameliorated sepsis induced by caecal ligation and puncture. In lung tissue from septic mice and in cultured macrophages, seselin down-regulated levels of proinflammatory factors and activity of STAT1 and p65, the master signal pathway molecules for polarization of macrophages into the proinflammatory phenotype. Importantly, adoptive transfer of bone marrow-derived macrophages, pretreated with seselin, lowered systemic proinflammatory factors in mice challenged with LPS. The underlying mechanism was that seselin targeted Jak2 to block interaction with IFNγ receptors and downstream STAT1. CONCLUSIONS AND IMPLICATIONS: Seselin exhibited anti-inflammatory activity through its action on Jak2. These results indicated a possible application of seselin to the treatment of inflammatory disease via blocking the development of the proinflammatory phenotype of macrophages.

A novel combination of astilbin and low-dose methotrexate respectively targeting A2AAR and its ligand adenosine for the treatment of collagen-induced arthritis.

Methotrexate (MTX) is widely used for rheumatoid arthritis (RA) treatment with frequently serious adverse effects. Therefore, combination of low-dose MTX with other drugs is often used in clinic. In this study, we investigated the improvement of astilbin and low-dose MTX combination on collagen-induced arthritis in DBA/1J mice. Results showed that the clinic score, incidence rate, paw swelling, pathological changes of joints and rheumatoid factors were more alleviated in combination therapy than MTX or astilbin alone group. Elevated antibodies (IgG, IgG1, IgG2a, IgM and anti-collagen IgG) and pro-inflammatory cytokines (IL-1ß, IL-6, TNF-α, IFN-γ and IL-17A) in serum were significantly inhibited, while anti-inflammatory cytokine, IL-10, was enhanced by combination therapy. Further studies indicated that combination therapy significantly decreased Th1 and Th17 cell differentiation and increased Treg cell differentiation. Mechanisms analysis demonstrated combination therapy greatly inhibited Con A-activated MAPK and inflammatory transcriptional signals. Moreover, MTX activated adenosine release and astilbin specifically up-regulated A2A adenosine receptor (A2AAR) expression simultaneously, which most probably contributed to the synergistic efficacy of combination therapy. ZM241385, a specific antagonist of A2AAR, greatly blocked the effects of combination therapy on T cell functions and downstream pathways. All these findings suggest that astilbin is a valuable candidate for low-dose MTX combined therapy in RA via increasing A2AAR/adenosine system and decreasing ERK/NFκB/STATs signals.

A fumigaclavine C isostere alleviates Th1-mediated experimental colitis via competing with IFN-γ for binding to IFN-γ receptor 1.

Interferon gamma (IFN-γ) signaling in T cells plays an important role in developing T helper 1 (Th1)-mediated inflammation. Selective regulation of IFN-γ signaling is an attractive strategy for treating Th1-mediated immune diseases. In this study, we aimed to explore possible means of targeting IFN-γ signaling by using small molecule compound. A synthetic small molecule FC9 was identified as it selectively inhibited IFN-γ signaling in T cells without suppressing interleukin 4 (IL-4) signaling. Furthermore, FC9 inhibited IFN-γ-induced Janus kinase 2 (JAK2) activation via competing with IFN-γ for binding to IFN-γ receptor 1 (IFN-γ R1). Interestingly, we found that FC9 bound to IFN-γ R1 and selectively suppressed Th1 but not Th2 immune response in T cells, resulting in an improvement in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. In conclusion, FC9-induced competitive blockade of IFN-γ R1 for selective inhibition of IFN-γ signaling, demonstrated a novel mean of targeting IFN-γ signaling. These findings could lead to increased options for the treatment of Crohn's disease and other Th1-mediated inflammatory diseases.

CUG-binding protein 1 regulates HSC activation and liver fibrogenesis.

Excessive activation of hepatic stellate cells (HSCs) is a key step in liver fibrogenesis. Here we report that CUG-binding protein 1 (CUGBP1) expression is elevated in HSCs and positively correlates with liver fibrosis severity in human liver biopsies. Transforming growth factor-beta (TGF-ß) selectively increases CUGBP1 expression in cultured HSCs in a p38 mitogen-activated protein kinase (MAPK)-dependent manner. Knockdown of CUGBP1 inhibits alpha smooth muscle actin (α-SMA) expression and promotes interferon gamma (IFN-γ) production in HSCs in vitro. We further show that CUGBP1 specifically binds to the 3' untranslated region (UTR) of human IFN-γ mRNA and promotes its decay. In mice, knockdown of CUGBP1 alleviates, whereas its overexpression exacerbates, bile duct ligation (BDL)-induced hepatic fibrosis. Therefore, CUGBP1-mediated IFN-γ mRNA decay is a key event for profibrotic TGF-ß-dependent activation of HSCs, and inhibiting CUGBP1 to promote IFN-γ signalling in activated HSCs could be a novel strategy to treat liver fibrosis.

Sunitinib, a Small-Molecule Kinase Inhibitor, Attenuates Bleomycin-Induced Pulmonary Fibrosis in Mice.

Idiopathic pulmonary fibrosis (IPF) is a chronic and ultimately fatal disease, characterized by excessive accumulation of fibroblasts, extensive deposition of extracellular matrix, and destruction of alveolar architecture. IPF is associated with an epithelial-dependent fibroblast-activated process, termed the epithelial-to-mesenchymal transition (EMT). However, there is still a lack of strategies to target EMT for the treatment of IPF. Sunitinib, a small-molecule multi-targeted tyrosine kinase inhibitor, targets multiple kinases that may play an important role in developing pulmonary fibrosis. Here, we explored the therapeutic potential of sunitinib using a mouse model of pulmonary fibrosis. Mice received intratracheal instillation of bleomycin (BLM). Then, the mice were intragastrically administrated with sunitinib or normal saline until the end of the experiment. Distinguished destruction of pulmonary architecture, conspicuous proliferation of fibroblasts and extensive deposition of collagen fibers were found in BLM mice. Sunitinib attenuated the pulmonary fibrosis and inhibited the accumulation of fibroblasts in the lung of BLM mice. To investigate if the inhibition of fibroblast accumulation in the lung by sunitinib was associated with EMT, we used human bronchial epithelial cells (HBEs) and W138 human lung fibroblasts. Sunitinib suppressed the degree of EMT induced by TGF-ß, a profibrotic factor, in HBEs and the proliferation of WI38 fibroblasts. Moreover, sunitinib reduced the degree of phosphorylation of serine residues on Smad2/3 that was induced by TGF-ß in HBEs. As EMT and accumulation of fibroblasts are critical for the development of pulmonary fibrosis, targeting multiple pro-fibrosis signaling pathways with sunitinib may be a novel strategy to treat pulmonary fibrosis.