Modelling atopic dermatitis in healthy human skin for the characterization of topical compounds.

Suitable human models for the development and characterization of topical compounds for inflammatory skin diseases such as atopic dermatitis are not readily available to date. We describe here the development of a translational model involving healthy human skin mimicking major aspects of AD and its application for the characterization of topical Janus kinase inhibitors. Full thickness human abdominal skin obtained from plastic surgery stimulated in vitro with IL4 and IL13 shows molecular features of AD. This is evidenced by STAT6 phosphorylation assessed by immunohistochemistry and analysis of skin lysates. Broad transcriptome changes assessed by AmpliSeq followed by gene set variation analysis showed a consistent upregulation of gene signatures characterizing AD in this model. Topical application of experimental formulations of compounds targeting the JAK pathway to full thickness skin normalizes the molecular features of AD induced by IL4 and IL13 stimulation. The inhibitory effects of topical JAK inhibitors on molecular features of AD are supported by pharmacokinetic analysis. The model described here is suited for the characterization of topical compounds for AD and has the potential to be extended to other inflammatory skin diseases and pathophysiological pathways.

A first-in-class inhibitor of HSP110 to potentiate XPO1-targeted therapy in primary mediastinal B-cell lymphoma and classical Hodgkin lymphoma.

BACKGROUND: Primary mediastinal B-cell lymphoma (PMBL) and classical Hodgkin lymphoma (cHL) are distinct hematological malignancies of B-cell origin that share many biological, molecular, and clinical characteristics. In particular, the JAK/STAT signaling pathway is a driver of tumor development due to multiple recurrent mutations, particularly in STAT6. Furthermore, the XPO1 gene that encodes exportin 1 (XPO1) shows a frequent point mutation (E571K) resulting in an altered export of hundreds of cargo proteins, which may impact the success of future therapies in PMBL and cHL. Therefore, targeted therapies have been envisioned for these signaling pathways and mutations. METHODS: To identify novel molecular targets that could overcome the treatment resistance that occurs in PMBL and cHL patients, we have explored the efficacy of a first-in-class HSP110 inhibitor (iHSP110-33) alone and in combination with selinexor, a XPO1 specific inhibitor, both in vitro and in vivo. RESULTS: We show that iHSP110-33 decreased the survival of several PMBL and cHL cell lines and the size of tumor xenografts. We demonstrate that HSP110 is a cargo of XPO1wt as well as of XPO1E571K. Using immunoprecipitation, proximity ligation, thermophoresis and kinase assays, we showed that HSP110 directly interacts with STAT6 and favors its phosphorylation. The combination of iHSP110-33 and selinexor induces a synergistic reduction of STAT6 phosphorylation and of lymphoma cell growth in vitro and in vivo. In biopsies from PMBL patients, we show a correlation between HSP110 and STAT6 phosphorylation levels. CONCLUSIONS: These findings suggest that HSP110 could be proposed as a novel target in PMBL and cHL therapy.

CD200R activation on naïve T cells by B cells induces suppressive activity of T cells via IL-24.

CD200 is an anti-inflammatory protein that facilitates signal transduction through its receptor, CD200R, in cells, resulting in immune response suppression. This includes reducing M1-like macrophages, enhancing M2-like macrophages, inhibiting NK cell cytotoxicity, and downregulating CTL responses. Activation of CD200R has been found to modulate dendritic cells, leading to the induction or enhancement of Treg cells expressing Foxp3. However, the precise mechanisms behind this process are still unclear. Our previous study demonstrated that B cells in Peyer's patches can induce Treg cells, so-called Treg-of-B (P) cells, through STAT6 phosphorylation. This study aimed to investigate the role of CD200 in Treg-of-B (P) cell generation. To clarify the mechanisms, we used wild-type, STAT6 deficient, and IL-24 deficient T cells to generate Treg-of-B (P) cells, and antagonist antibodies (anti-CD200 and anti-IL-20RB), an agonist anti-CD200R antibody, CD39 inhibitors (ARL67156 and POM-1), a STAT6 inhibitor (AS1517499), and soluble IL-20RB were also applied. Our findings revealed that Peyer's patch B cells expressed CD200 to activate the CD200R on T cells and initiate the process of Treg-of-B (P) cells generation. CD200 and CD200R interaction triggers the phosphorylation of STAT6, which regulated the expression of CD200R, CD39, and IL-24 in T cells. CD39 regulated the expression of IL-24, which sustained the expression of CD223 and IL-10 and maintained the cell viability. In summary, the generation of Treg-of-B (P) cells by Peyer's patch B cells was through the CD200R-STAT6-CD39-IL-24 axis pathway.

Rabeprazole mitigates obesity-induced chronic inflammation and insulin resistance associated with increased M2-type macrophage polarization.

Macrophage polarization is closely associated with obesity-induced chronic inflammation and insulin resistance. Proton pump inhibitor Rabeprazole has long been used to treat gastritis and gastric ulcers. However, whether Rabeprazole plays a role in macrophage polarization during obesity is unknown. Here, we show that Rabeprazole suppresses M1-type macrophage-mediated inflammation, leads to increased M2-type macrophages and alters the polarization status from M1 to M2 in vitro. Mechanistically, Rabe-regulated macrophage polarization is associated with inhibition of NF-κB and activation of STAT6 signaling pathways. Furthermore, Rabeprazole induces M2-type adipose tissue macrophages and alleviates chronic inflammation, improving glucose tolerance and insulin sensitivity in high-fat diet-fed mice. In addition, Rabeprazole increases CD206+ M2-type liver macrophages and relieves liver inflammation, alleviating liver injury and lipid accumulation. Thus, our findings show that Rabeprazole effectively regulates macrophage polarization and controls obesity-associated chronic inflammation and insulin resistance, thus providing a potential therapeutic strategy against obesity-associated metabolic diseases.

Iguratimod prevents renal fibrosis in unilateral ureteral obstruction model mice by suppressing M2 macrophage infiltration and macrophage-myofibroblast transition.

Iguratimod is a novel synthetic, small-molecule immunosuppressive agent used to treat rheumatoid arthritis. Through ongoing exploration of its role and mechanisms of action, iguratimod has been observed to have antifibrotic effects in the lung and skin; however, its effect on renal fibrosis remains unknown. This study aimed to investigate whether iguratimod could affect renal fibrosis progression. Three different concentrations of iguratimod (30 mg/kg/day, 10 mg/kg/day, and 3 mg/kg/day) were used to intervene in unilateral ureteral obstruction (UUO) model mice. Iguratimod at 10 mg/kg/day was observed to be effective in slowing UUO-mediated renal fibrosis. In addition, stimulating bone marrow-derived macrophages with IL-4 and/or iguratimod, or with TGF-ß and iguratimod or SRC inhibitors in vitro, suggested that iguratimod mitigates the progression of renal fibrosis in UUO mice, at least in part, by inhibiting the IL-4/STAT6 signaling pathway to attenuate renal M2 macrophage infiltration, as well as by impeding SRC activation to reduce macrophage-myofibroblast transition. These findings reveal the potential of iguratimod as a treatment for renal disease.

The barrier-protective effect of ß-eudesmol against type 2-inflammatory cytokine-induced tight junction disassembly in airway epithelial cells.

Allergic inflammation, which is the pathogenesis of allergic rhinitis and asthma, is associated with disruption of the airway epithelial barrier due to the effects of type 2 inflammatory cytokines, i.e. interleukin-4 and interleukin-13 (IL-4/13). The anti-allergic inflammatory effect of ß-eudesmol (BE) on the tight junction (TJ) of the airway epithelium has not previously been reported. Herein, the barrier protective effect of BE was determined by measurement of transepithelial electrical resistance and by paracellular permeability assay in an IL-4/13-treated 16HBE14o- monolayer. Pre-treatment of BE concentration- and time- dependently inhibited IL-4/13-induced TJ barrier disruption, with the most significant effect observed at 20 µM. Cytotoxicity analyses showed that BE, either alone or in combination with IL-4/13, had no effect on cell viability. Western blot and immunofluorescence analyses showed that BE inhibited IL-4/13-induced mislocalization of TJ components, including occludin and zonula occludens-1 (ZO-1), without affecting the expression of these two proteins. In addition, the mechanism of the TJ-protective effect of BE was mediated by inhibition of IL-4/13-induced STAT6 phosphorylation, in which BE might serve as an antagonist of cytokine receptors. In silico molecular docking analysis demonstrated that BE potentially interacted with the site I pocket of the type 2 IL-4 receptor, likely at Asn-126 and Tyr-127 amino acid residues. It can therefore be concluded that BE is able to prevent IL-4/13-induced TJ disassembly by interfering with cytokine-receptor interaction, leading to suppression of STAT6-induced mislocalization of occludin and ZO-1. BE is a promising candidate for a therapeutic intervention for inflammatory airway epithelial disorders driven by IL-4/13.

MaiJiTong granule attenuates atherosclerosis by reducing ferroptosis via activating STAT6-mediated inhibition of DMT1 and SOCS1/p53 pathways in LDLR-/- mice.

BACKGROUND AND PURPOSE: Atherosclerosis is the primary pathological basis of cardiovascular disease. Ferroptosis is a regulated form of cell death, a process of lipid peroxidation driven by iron, which can initiate and promote atherosclerosis. STAT6 is a signal transducer that shows a potential role in regulating ferroptosis, but, the exact role in ferroptosis during atherogenesis remains unclear. The Traditional Chinese Medicine Maijitong granule (MJT) is used for treating cardiovascular disease and shows a potential inhibitory effect on ferroptosis. However, the antiatherogenic effect and the underlying mechanism remain unclear. In this study, we determined the role of STAT6 in ferroptosis during atherogenesis, investigated the antiatherogenic effect of MJT, and determined whether its antiatherogenic effect was dependent on the inhibition of ferroptosis. METHODS: 8-week-old male LDLR-/- mice were fed a high-fat diet (HFD) at 1st and 10th week, respectively, to assess the preventive and therapeutic effects of MJT on atherosclerosis and ferroptosis. Simultaneously, the anti-ferroptotic effects and mechanism of MJT were determined by evaluating the expression of genes responsible for lipid peroxidation and iron metabolism. Subsequently, we reanalyzed microarray data in the GSE28117 obtained from cells after STAT6 knockdown or overexpression and analyzed the correlation between STAT6 and ferroptosis. Finally, the STAT6-/- mice were fed HFD and injected with AAV-PCSK9 to validate the role of STAT6 in ferroptosis during atherogenesis and revealed the antiatherogenic and anti-ferroptotic effect of MJT. RESULTS: MJT attenuated atherosclerosis by reducing plaque lesion area and enhancing plaque stability in both preventive and therapeutic groups. MJT reduced inflammation via suppressing inflammatory cytokines and inhibited foam cell formation by lowering the LDL level and promoting ABCA1/G1-mediated lipid efflux. MJT ameliorated the ferroptosis by reducing lipid peroxidation and iron dysregulation during atherogenesis. Mechanistically, STAT6 negatively regulated ferroptosis by transcriptionally suppressing SOCS1/p53 and DMT1 pathways. MJT suppressed the DMT1 and SOCS1/p53 via stimulating STAT6 phosphorylation. In addition, STAT6 knockout exacerbated atherosclerosis and ferroptosis, which abolished the antiatherogenic and anti-ferroptotic effects of MJT. CONCLUSION: STAT6 acts as a negative regulator of ferroptosis and atherosclerosis via transcriptionally suppressing DMT1 and SOCS1 expression and MJT attenuates atherosclerosis and ferroptosis by activating the STAT6-mediated inhibition of DMT1 and SOCS1/p53 pathways, which indicated that STAT6 acts a novel promising therapeutic target to ameliorate atherosclerosis by inhibiting ferroptosis and MJT can serve as a new therapy for atherosclerosis treatment.

25-Hydroxycholesterol regulates lysosome AMP kinase activation and metabolic reprogramming to educate immunosuppressive macrophages.

Macrophages are critical to turn noninflamed "cold tumors" into inflamed "hot tumors". Emerging evidence indicates abnormal cholesterol metabolites in the tumor microenvironment (TME) with unclear function. Here, we uncovered the inducible expression of cholesterol-25-hydroxylase (Ch25h) by interleukin-4 (IL-4) and interleukin-13 (IL-13) via the transcription factor STAT6, causing 25-hydroxycholesterol (25HC) accumulation. scRNA-seq analysis confirmed that CH25Hhi subsets were enriched in immunosuppressive macrophage subsets and correlated to lower survival rates in pan-cancers. Targeting CH25H abrogated macrophage immunosuppressive function to enhance infiltrating T cell numbers and activation, which synergized with anti-PD-1 to improve anti-tumor efficacy. Mechanically, lysosome-accumulated 25HC competed with cholesterol for GPR155 binding to inhibit the kinase mTORC1, leading to AMPKα activation and metabolic reprogramming. AMPKα also phosphorylated STAT6 Ser564 to enhance STAT6 activation and ARG1 production. Together, we propose CH25H as an immunometabolic checkpoint, which manipulates macrophage fate to reshape CD8+ T cell surveillance and anti-tumor response.

PTPRO inhibition ameliorates spinal cord injury through shifting microglial M1/M2 polarization via the NF-κB/STAT6 signaling pathway.

Spinal cord injury (SCI) induces severe neuroinflammation, and subsequently neurological dysfunction. Activated microglia are critical for modulation of neuroinflammation. Protein tyrosine phosphatase receptor type O (PTPRO), a member of protein tyrosine phosphatases (PTPs), exerts a pro-inflammatory role in multiple human diseases; however, its role in SCI remains unclarified. Here, a T7 spinal cord compression injury model was established in Sprague-Dawley (SD) rats, and PTPRO expression was upregulated in injured spinal cord and microglia after SCI. Microglia M1 and M2 polarization in vitro were induced using LPS/IFN-γ and IL-4, respectively. PTPRO expression was elevated in M1-polarized microglia, and PTPRO downregulation mediated by PTPRO shRNA (shPTPRO) decreased CD86+ cell proportion, iNOS, TNF-α, IL-1ß, and IL-6 levels, and p65 phosphorylation. PTPRO was downregulated in M2 microglia, and PTPRO upregulation by PTPRO overexpression plasmid (OE-PTPRO) reduced CD206+ cell percentage, Arg-1, IL-10, and TGF-ß1 levels and STAT6 phosphorylation. Mechanistically, the transcription factor SOX4 elevated PTPRO expression and its promoter activity. SOX4 overexpression enhanced M1 polarization and p65 phosphorylation, while its knockdown promoted M2 polarization and STAT6 phosphorylation. PTPRO might mediate the function of SOX4 in BV2 microglia polarization. Furthermore, lentivirus-mediated downregulation of PTPRO following SCI improved locomotor functional recovery, demonstrated by elevated BBB scores, incline angle, consistent hindlimb coordination, and reduced lesion area and neuronal apoptosis. PTPRO downregulation promoted microglia M2 polarization, NF-κB inactivation and STAT6 activation after injury. In conclusion, PTPRO inhibition improves spinal cord injury through facilitating M2 microglia polarization via the NF-κB/STAT6 signaling pathway, which is probably controlled by SOX4.

Increased SERPINB2 potentiates 15LO1 expression via STAT6 signalling in epithelial cells in eosinophilic chronic rhinosinusitis with nasal polyps.

BACKGROUND: SERPINB2, a biomarker of Type-2 (T2) inflammatory processes, has been described in the context of asthma. Chronic rhinosinusitis with nasal polyps (CRSwNP) is also correlated with T2 inflammation and elevated 15LO1 induced by IL-4/13 in nasal epithelial cells. The aim of this study was to evaluate the expression and location of SERPINB2 in nasal epithelial cells (NECs) and determine whether SERPINB2 regulates 15LO1 and downstream T2 markers in NECs via STAT6 signalling. METHODS: SERPINB2 gene expression in bulk and single-cell RNAseq database was analysed by bioinformatics analysis. SERPINB2, 15LO1 and other T2 markers were evaluated from CRSwNP and HCs NECs. The colocalization of SERPINB2 and 15LO1 was evaluated by immunofluorescence. Fresh NECs were cultured at an air-liquid interface with or without IL-13, SERPINB2 Dicer-substrate short interfering RNAs (DsiRNAs) transfection, exogenous SERPINB2, 15-HETE recombinant protein and pSTAT6 inhibitors. 15LO1, 15-HETE and downstream T2 markers were analysed by qRT-PCR, western blot and ELISA. RESULTS: SERPINB2 expression was increased in eosinophilic nasal polyps compared with that in noneosinophilic nasal polyps and control tissues and positively correlated with 15LO1 and other downstream T2 markers. SERPINB2 was predominantly expressed by epithelial cells in NP tissue and was colocalized with 15LO1. In primary NECs in vitro, SERPINB2 expression was induced by IL-13. Knockdown or overexpression SERPINB2 decreased or enhanced expression of 15LO1 and 15-HETE in NECs, respectively, in a STAT6-dependent manner. SERPINB2 siRNA also inhibited the expression of the 15LO1 downstream genes, such as CCL26, POSTN and NOS2. STAT6 inhibition similarly decreased SERPINB2-induced 15LO1. CONCLUSIONS: SERPINB2 is increased in NP epithelial cells of eosinophilic CRSwNP (eCRSwNP) and contributes to T2 inflammation via STAT6 signalling. SERPINB2 could be considered a novel therapeutic target for eCRSwNP.

Exosome circATP8A1 induces macrophage M2 polarization by regulating the miR-1-3p/STAT6 axis to promote gastric cancer progression.

Circular RNAs (circRNAs) play important roles in gastric cancer progression but the regulatory role of circRNAs in controlling macrophage function remains elusive. Exosomes serve as cargo for circRNAs and play a crucial role as mediators in facilitating communication between cancer cells and the tumor microenvironment. In this study, we found that circATP8A1, a previously unreported circular RNA, is highly expressed in both gastric cancer tissues and exosomes derived from plasma. Increased circATP8A1 was associated with advanced TNM stage and worse prognosis in patients with gastric cancer. We showed that  the circATP8A1 knockdown significantly inhibited gastric cancer proliferation and invasion in vitro and in vivo. Functionally, exosome circATP8A1 induced the M2 polarization of macrophages through the STAT6 pathway instead of the STAT3 pathway. Mechanistically, circATP8A1 was shown to activate the STAT6 pathway through competitive binding to miR-1-3p, as confirmed by Fluorescence In Situ Hybridization (FISH), RNA immunoprecipitation, RNA pulldown, and Luciferase reporter assays. The reversal of circATP8A1-induced STAT6 pathway activation and macrophage polarization was observed upon blocking miR-1-3p. Macrophages treated with exosomes from gastric cancer cells overexpressing circATP8A1 were able to promote gastric cancer migration, while knockdown of circATP8A1 reversed these effects in vivo. In summary, exosome-derived circATP8A1 from gastric cancer cells induce macrophages M2 polarization via the circATP8A1/miR-1-3p/STAT6 axis, and tumor progression. Our results highlight circATP8A1 as a potential prognostic biomarker and therapeutic target in gastric cancer.

Wogonoside Ameliorates Airway Inflammation and Mucus Hypersecretion via NF-κB/STAT6 Signaling in Ovalbumin-Induced Murine Acute Asthma.

Asthma is recognized as a chronic respiratory illness characterized by airway inflammation and airway hyperresponsiveness. Wogonoside, a flavonoid glycoside, is reported to significantly alleviate the inflammation response and oxidative stress. Herein, this study aimed to investigate the therapeutic effect and underlying mechanism of wogonoside on airway inflammation and mucus hypersecretion in a murine asthma model and in human bronchial epithelial cells (16HBE). BALB/c mice were sensitized and challenged with ovalbumin (OVA). Pulmonary function and the number of cells in the bronchoalveolar lavage fluid (BALF) were examined. Pathological changes in lung tissue in each group were evaluated via hematoxylin and eosin and periodic acid-Schiff staining, and changes in levels of cytokines in BALF and of immunoglobulin E in serum were determined via an enzyme-linked immunosorbent assay. The expression of relevant genes in lung tissue was analyzed via real-time PCR. Western blotting and immunofluorescence were employed to detect the expression of relevant proteins in lung tissue and 16HBE cells. Treatment with 10 and 20 mg/kg wogonoside significantly attenuated the OVA-induced increase of inflammatory cell infiltration, mucus secretion, and goblet cell percentage and improved pulmonary function. Wogonoside treatment reduced the level of T-helper 2 cytokines including interleukin (IL)-4, IL-5, and IL-13 in BALF and of IgE in serum and decreased the mRNA levels of cytokines (IL-4, IL-5, IL-6, IL-13, and IL-1ß and tumor necrosis factor-α), chemokines (CCL-2, CCL-11, and CCL-24), and mucoproteins (MUC5AC, MUC5B, and GOB5) in lung tissues. The expression of MUC5AC and the phosphorylation of STAT6 and NF-κB p65 in lung tissues and 16HBE cells were significantly downregulated after wogonoside treatment. Thus, wogonoside treatment may effectively decrease airway inflammation, airway remodeling, and mucus hypersecretion via blocking NF-κB/STAT6 activation.

Targeting STAT6-mediated synovial macrophage activation improves pain in experimental knee osteoarthritis.

BACKGROUND: Pain from osteoarthritis (OA) is one of the top causes of disability worldwide, but effective treatment is lacking. Nociceptive factors are released by activated synovial macrophages in OA, but depletion of synovial macrophages paradoxically worsens inflammation and tissue damage in previous studies. Rather than depleting macrophages, we hypothesized that inhibiting macrophage activation may improve pain without increasing tissue damage. We aimed to identify key mechanisms mediating synovial macrophage activation and test the role of STAT signaling in macrophages on pain outcomes in experimental knee OA. METHODS: We induced experimental knee OA in rats via knee destabilization surgery, and performed RNA sequencing analysis on sorted synovial tissue macrophages to identify macrophage activation mechanisms. Liposomes laden with STAT1 or STAT6 inhibitors, vehicle (control), or clodronate (depletion control) were delivered selectively to synovial macrophages via serial intra-articular injections up to 12 weeks after OA induction. Treatment effects on knee and hindpaw mechanical pain sensitivity were measured during OA development, along with synovitis, cartilage damage, and synovial macrophage infiltration using histopathology and immunofluorescence. Lastly, crosstalk between drug-treated synovial tissue and articular chondrocytes was assessed in co-culture. RESULTS: The majority of pathways identified by transcriptomic analyses in OA synovial macrophages involve STAT signaling. As expected, macrophage depletion reduced pain, but increased synovial tissue fibrosis and vascularization. In contrast, STAT6 inhibition in macrophages led to marked, sustained improvements in mechanical pain sensitivity and synovial inflammation without worsening synovial or cartilage pathology. During co-culture, STAT6 inhibitor-treated synovial tissue had minimal effects on healthy chondrocyte gene expression, whereas STAT1 inhibitor-treated synovium induced changes in numerous cartilage turnover-related genes. CONCLUSION: These results suggest that STAT signaling is a major mediator of synovial macrophage activation in experimental knee OA. STAT6 may be a key mechanism mediating the release of nociceptive factors from macrophages and the development of mechanical pain sensitivity. Whereas therapeutic depletion of macrophages paradoxically increases inflammation and fibrosis, blocking STAT6-mediated synovial macrophage activation may be a novel strategy for OA-pain management without accelerating tissue damage.

23-Hydroxybetulinic acid attenuates 5-fluorouracil resistance of colorectal cancer by modulating M2 macrophage polarization via STAT6 signaling.

Macrophage polarization is closely associated with the inflammatory processes involved in the development and chemoresistance of colorectal cancer (CRC). M2 macrophages, the predominant subtype of tumor-associated macrophages (TAMs) in a wide variety of malignancies, have been demonstrated to promote the resistance of CRC to multiple chemotherapeutic drugs, such as 5-fluorouracil (5-FU). In our study, we investigated the potential of 23-Hydroxybetulinic Acid (23-HBA), a significant active component of Pulsatilla chinensis (P. chinensis), to inhibit the polarization of M2 macrophages induced by IL-4. Our results showed that 23-HBA reduced the expression of M2 specific marker CD206, while downregulating the mRNA levels of M2 related genes (CD206, Arg1, IL-10, and CCL2). Additionally, 23-HBA effectively attenuated the inhibitory effects of the conditioned medium from M2 macrophages on apoptosis in colorectal cancer SW480 cells. Mechanistically, 23-HBA prevented the phosphorylation and nuclear translocation of the STAT6 protein, resulting in the inhibition of IL-10 release in M2 macrophages. Moreover, it interfered with the activation of the IL-10/STAT3/Bcl-2 signaling pathway in SW480 cells, ultimately reducing M2 macrophage-induced resistance to 5-FU. Importantly, depleting STAT6 expression in macrophages abolished the suppressive effect of 23-HBA on M2 macrophage polarization, while also eliminating its ability to decrease M2 macrophage-induced 5-FU resistance in cancer cells. Furthermore, 23-HBA significantly diminished the proportion of M2 macrophages in the tumor tissues of colorectal cancer mice, simultaneously enhancing the anti-cancer efficacy of 5-FU. The findings presented in this study highlight the capacity of 23-HBA to inhibit M2 macrophage polarization, a process that contributes to reduced 5-FU resistance in colorectal cancer.

EGFR overexpression and macrophage infiltration correlate with poorer prognosis in HPV-negative oropharyngeal cancer via STAT6 signaling.

BACKGROUND: The prevalence of HPV-negative oropharyngeal cancer (OPC) is higher in Asian countries. Patients with HPV-negative OPC suffer poor outcomes. Multi-omics analysis could provide researchers and clinicians with more treatment targets for this high-risk group. We aimed to explore the prognostic significance of EGFR overexpression and macrophage infiltration in OPC, especially HPV-negative OPC in this study. METHODS: EGFR alternation was evaluated with TCGA, PanCancer Atlas through cBioProtal. EGFR mRNA expression in HPV-negative head and neck squamous cell carcinoma was analyzed using the Tumor Immune Estimation Resource (TIMER 2.0). We also examined EGFR/STAT6/MRC1 expression in paraffin-embedded tissues from a p16-negative OPC cohort. The correlation between EGFR expression and macrophage activation was explored using Person's correlation coefficient. The impact of biomarkers or macrophage infiltration on 5-year overall survival and recurrence-free survival were analyzed using Kaplan-Meier survival curves. RESULTS: EGFR alteration rate was 15%, 13%, and 0% for HPV-negative HNSCC (excluding OPC), HPV-negative OPC, and HPV-positive OPC. High EGFR expression was associated with increased tumor infiltration of immune cells, such as macrophages. We observed positive correlations between EGFR, STAT6, and MRC1 expression in p16-negative OPC. Higher MRC1 expression was associated with poorer survival rates. CONCLUSIONS: There is strong correlation between EGFR overexpression and M2 polarization in patients with p16-negative OPC. Immunotherapy with or without EGFR inhibitor could be considered in these high-risk patients.

Solitary fibrous tumor occurring in the colon as submucosal mesenchymal lesion: report of two cases and review of the literature.

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm most often arising from the pleura and rarely in extra-pleural locations, including the gastrointestinal tract. We describe two cases of a SFT presenting as submucosal colonic lesion and review the literature on this lesion. One submucosal lesion was localized in the cecum and was 10 mm in size. The second lesion presented as a 17 mm submucosal rectal lesion. Both lesions presented as well-circumscribed submucosal lesions arranged in short fascicles, blending with abundant collagenous stroma. In both cases, the spindle cells were positive for CD34, STAT6 and CD99, and molecular studies showed NAB2:STAT6 fusion supporting the diagnosis of SFT. Both patients are alive and well 10 and 5 years post-excision, respectively. In conclusion, SFT can occur in the colon as a submucosal lesion and should be included in the differential diagnosis of colonic mesenchymal lesions.

Solitary fibrous tumor: Can the new Huang risk stratification system for orbital tumors improve prognostic accuracy in other tumor locations?

Solitary fibrous tumors (SFTs) are known for their heterogeneous morphology, characterized by a variety of cell shapes and different growth patterns. They can also arise in various anatomical locations, most commonly in extremities and deep soft tissues. Despite this diversity in morphology and location, all SFTs share a common molecular signature involving the NAB2::STAT6 gene fusion. Due to their unpredictable clinical behavior, establishing prognostic factors is crucial. This study aims to evaluate an orbital risk stratification system (RSS) proposed by Huang et al. for use in extraorbital SFTs using a database of 97 cases. The Huang model takes into consideration tumor size, mitotic figures, Ki-67 index, and dominant constituent cell (DCC) as key variables. Survival analysis confirmed the model's predictive value, with higher-risk scores being associated with poorer outcomes. However, in contrast to the orbital SFTs studied by Huang et al., our study did not find a correlation between tumor size and recurrence in extraorbital cases. While the Huang model performs slightly better than other RSS, it falls short on achieving statistical significance in distinguishing recurrence risk groups in extraorbital locations. In conclusion, this study validates the Huang RSS for use in extraorbital SFTs and underscores the importance of considering DCC, mitotic count, and Ki-67 together. However, we found that including tumor size in this model did not improve prognostic significance in extraorbital SFTs. Despite the benefits of this additional RSS, vigilant monitoring remains essential, even in cases classified as low-risk due to the inherent unpredictability of SFT clinical outcomes.

Enantiomer-Dependent Supramolecular Immunosuppressive Modulation for Tissue Reconstruction.

Modulating the properties of biomaterials in terms of the host immune response is critical for tissue repair and regeneration. However, it is unclear how the preference for the cellular microenvironment manipulates the chiral immune responses under physiological or pathological conditions. Here, we reported that in vivo and in vitro oligopeptide immunosuppressive modulation was achieved by manipulation of macrophage polarization using chiral tetrapeptide (Ac-FFFK-OH, marked as FFFK) supramolecular polymers. The results suggested that chiral FFFK nanofibers can serve as a defense mechanism in the restoration of tissue homeostasis by upregulating macrophage M2 polarization via the Src-STAT6 axis. More importantly, transiently acting STAT6, insufficient to induce a sustained polarization program, then passes the baton to EGR2, thereby continuously maintaining the M2 polarization program. It is worth noting that the L-chirality exhibits a more potent effect in inducing macrophage M2 polarization than does the D-chirality, leading to enhanced tissue reconstruction. These findings elucidate the crucial molecular signals that mediate chirality-dependent supramolecular immunosuppression in damaged tissues while also providing an effective chiral supramolecular strategy for regulating macrophage M2 polarization and promoting tissue injury repair based on the self-assembling chiral peptide design.

Myeloid Deletion of Cdc42 Protects Liver From Hepatic Ischemia-Reperfusion Injury via Inhibiting Macrophage-Mediated Inflammation in Mice.

BACKGROUND & AIMS: Hepatic ischemia-reperfusion injury (HIRI) often occurs in liver surgery, such as partial hepatectomy and liver transplantation, in which myeloid macrophage-mediated inflammation plays a critical role. Cell division cycle 42 (Cdc42) regulates cell migration, cytoskeleton rearrangement, and cell polarity. In this study, we explore the role of myeloid Cdc42 in HIRI. METHODS: Mouse HIRI models were established with 1-hour ischemia followed by 12-hour reperfusion in myeloid Cdc42 knockout (Cdc42mye) and Cdc42flox mice. Myeloid-derived macrophages were traced with RosamTmG fluorescent reporter under LyzCre-mediated excision. The experiments for serum or hepatic enzymic activities, histologic and immunologic analysis, gene expressions, flow cytometry analysis, and cytokine antibody array were performed. RESULTS: Myeloid deletion of Cdc42 significantly alleviated hepatic damages with the reduction of hepatic necrosis and inflammation, and reserved hepatic functions following HIRI in mice. Myeloid Cdc42 deficiency suppressed the infiltration of myeloid macrophages, reduced the secretion of proinflammatory cytokines, restrained M1 polarization, and promoted M2 polarization of myeloid macrophages in livers. In addition, inactivation of Cdc42 promoted M2 polarization via suppressing the phosphorylation of STAT1 and promoting phosphorylation of STAT3 and STAT6 in myeloid macrophages. Furthermore, pretreatment with Cdc42 inhibitor, ML141, also protected mice from hepatic ischemia-reperfusion injury. CONCLUSIONS: Inhibition or deletion of myeloid Cdc42 protects liver from HIRI via restraining the infiltration of myeloid macrophages, suppressing proinflammatory response, and promoting M2 polarization in macrophages.

STAT6 mutations enriched at diffuse large B-cell lymphoma relapse reshape the tumor microenvironment.

Diffuse large B-cell lymphoma (DLBCL) relapses in approximately 40% of patients following frontline therapy. We reported that STAT6D419 mutations are enriched in relapsed/refractory DLBCL (rrDLBCL) samples, suggesting that JAK/STAT signaling plays a role in therapeutic resistance. We hypothesized that STAT6D419 mutations can improve DLBCL cell survival by reprogramming the microenvironment to sustain STAT6 activation. Thus, we investigated the role of STAT6D419 mutations on DLBCL cell growth and its microenvironment. We found that phospho-STAT6D419N was retained in the nucleus longer than phospho-STAT6WT following IL-4 stimulation, and STAT6D419N recognized a more restricted DNA-consensus sequence than STAT6WT. Upon IL-4 induction, STAT6D419N expression led to a higher magnitude of gene expression changes, but in a more selective list of gene targets compared with STATWT. The most significantly expressed genes induced by STAT6D419N were those implicated in survival, proliferation, migration, and chemotaxis, in particular CCL17. This chemokine, also known as TARC, attracts helper T-cells to the tumor microenvironment, especially in Hodgkin's lymphoma. To this end, in DLBCL, phospho-STAT6+ rrDLBCL cells had a greater proportion of infiltrating CD4+ T-cells than phospho-STAT6- tumors. Our findings suggest that STAT6D419 mutations in DLBCL lead to cell autonomous changes, enhanced signaling, and altered composition of the tumor microenvironment.