Apigenin alleviates Sjögren's syndrome-induced salivary gland epithelial cell ferroptosis via ERα signaling-mediated regulation of the ATF3/SLC7A1l axis

BACKGROUND

In Sjögren's syndrome (SS)-an autoimmune disease characterized by dry mouth and eyes-salivary gland epithelial cells (SGECs) undergo ferroptosis, which disrupts their integrity and impairs saliva secretion. Apigenin, a phytoestrogen, is known to activate estrogen signalling and alleviate xerostomia in ovariectomized mice; however, its effect on SGEC survival and function in SS remains unclear. We hypothesized that apigenin alleviates SS symptoms and progression by inhibiting ferroptosis in SGECs and aimed to elucidate the underlying mechanism.

METHODS

Apigenin (50 mg/kg) was orally gavaged to non-obese diabetic (NOD)/LtJ female mice (SS model); changes in SS functional indicators were analyzed using mRNA sequencing and bioinformatic analyses of submandibular glands. Interferon-gamma (IFN-γ)-stimulated SGECs were used to model SS in vitro; SGEC activity and aquaporin 5 (AQP5) expression were analyzed. Immunohistochemical staining, transmission electron microscopy, RT-qPCR, western blotting and other methods were used to verify the mechanisms.

RESULTS

Apigenin significantly increased salivary secretion and AQP5 expression while inhibiting ferroptosis and immune infiltration in NOD mouse submandibular glands. The oxidative stress gene ATF3 was upregulated and GPX4 was downregulated in NOD mice compared to that in control group (ICR mice); however, apigenin reversed this effect. IFN-γ treatment downregulated AQP5, SLC7A11, and GPX4 expression while promoting ATF3 expression and ferroptosis, which was mitigated by apigenin. ATF3 knockdown increased SLC7A11 and GPX4 expression, inhibiting SS and ferroptosis. Furthermore, apigenin inhibited ferroptosis in SGECs through ESR1 binding to ATF3.

CONCLUSION

Apigenin alleviates SS by regulating SGEC ferroptosis via the ERα-regulated ATF3/SLC7A11 axis, highlighting its therapeutic potential in SS.

PANoptosis Features, a Humanized NSG Murine Model of Sjogren's Syndrome

Sjogren's syndrome (SS) is a complex systemic autoimmune disease. This study aims to elucidate a humanized NOD-PrkdcscidIl2rgem1/Smoc (NSG) murine model to better clarify the pathogenesis of SS. NSG female mice were adoptively transferred with 10 million peripheral blood mononuclear cells (PBMCs) through the tail vein from healthy controls (HCs), primary Sjogren's syndrome (pSS), and systemic lupus erythematosus (SLE) patients on D0. The mice were subcutaneously injected with C57/B6j submandibular gland (SG) protein or phosphate-buffered saline on D3, D17 and D31, respectively. NSG mice were successfully transplanted with human PBMCs. Compared with NSG-HC group, NSG-pSS and NSG-SLE mice exhibited a large number of lymphocytes infiltration in the SG, decreased salivary flow rate, lung involvement, decreased expression of genes related to salivary secretion, and the production of autoantibodies. Type I interferon-related genes were increased in the SG of NSG-pSS and NSG-SLE mice. The ratio of BAX/BCL2, BAX, cleaved caspase3, and TUNEL staining were increased in the SG of NSG-pSS and NSG-SLE mice. The expressions of p-MLKL and p-RIPK3 were increased in the SG of NSG-pSS and NSG-SLE mice. Increased expression of type I interferon-related genes, PANoptosis (apoptosis and necroptosis) were identified in the SG of this typical humanized NSG murine model of SS.

Carbon quantum dots as immune modulatory therapy in a Sjögren's syndrome mouse model

OBJECTIVES

The objective of the study was to evaluate the therapeutic effects of carbon quantum dots (CQDs) in immunomodulation on non-obese diabetic (NOD) mice, as the model for Sjögren's syndrome (SS).

METHODS

Carbon quantum dots were generated from Setaria viridis via a hydrothermal process. Their toxic effects were tested by cell viability and blood chemistry analysis, meanwhile therapeutic effects were investigated in NOD mice in the aspects of saliva flow, histology, and immune cell distribution.

RESULTS

Carbon quantum dots, with rich surface chemistry and unique optical properties, showed non-cytotoxicity in vitro or no damage in vivo. Intravenously applied CQDs alleviated inflammation in the submandibular glands in NOD mice after 6-week treatments. The inflammatory area index and focus score were significantly decreased in CQD-treated mice. Besides, the levels of anti-SSA and anti-SSB were decreased in the presence of CQDs. The stimulated saliva flow rates and weight of submandibular glands were significantly increased in CQD-treated mice by reducing the apoptosis of cells. The CD3+ and CD4+ T cells distributed around the ducts of submandibular glands were significantly decreased, while the percentage of Foxp3+ cells was higher in CQD-treated mice than that in the control group.

CONCLUSIONS

Our findings suggest that CQDs may ameliorate the dysregulated immune processes in NOD mice.

Effects of iguratimod on inflammatory factors and apoptosis of submandibular gland epithelial cells in NOD mice

Non-obese diabetic (NOD) mice were taken as primary Sjögren's syndrome (pSS) model mice to examine the therapeutic impact of iguratimod (IGU) on inflammatory factors levels and apoptosis of submandibular epithelial cells, and provide experimental basis for the treatment of pSS by iguratimod. Twenty-four NOD murine models were divided into the model, high-dose (IGU 30 mg/kg) and low-dose (IGU 10 mg/kg) groups, eight mice per group. The normal control group comprised eight C57B/L mice. From 8 weeks of age, the NOD mice were administered IGU by intragastric gavage administration every day for 8 weeks; their water consumption, saliva secretion, submandibular gland, and spleen indices were measured. The levels of serum inflammatory factor (IL-1β, TNF-α, IL-6, and IL-17) were evaluated, and Bax, caspase-3, and Bcl-2 levels were detected. The histological alterations in the submandibular glands were discovered. IGU can reduce the water intake of NOD mice (p < 0.01), increase the saliva secretion and the submandibular gland index (p < 0.01); reduce the spleen index and the serum inflammatory factors (p < 0.01); improve the pathological tissue damage and cell apoptosis of the submandibular gland (p < 0.05). IGU can reduce the expression levels of inflammatory mediators in the serum and the extent of lymphocyte infiltration and apoptosis in submandibular gland epithelial cells. It can also regulate apoptosis-related protein expression, thereby improving the secretory function of exocrine glands.

Vasoactive intestinal peptide exerts therapeutic action by regulating PTEN in a model of Sjögren's disease

INTRODUCTION

Sjögren's disease (SjD) is a chronic autoimmune disease characterized by the loss of the secretory function of the exocrine glands. At present, drugs that can both correct the immune imbalance and improve exocrine gland function are needed. Meanwhile, vasoactive intestinal peptide (VIP) has been reported as a candidate with anti-inflammatory and immunoregulatory properties for treating autoimmune diseases.

METHODS

Nonobese diabetic (NOD) mice and the primary splenic lymphocyte cells (SPLCs) were used to construct the SS model. The therapeutic effects of VIP for SjD by evaluating water consumption, histopathology, T cell subsets, and related cytokines. RT-qPCR and Western blot analysis were used to identify the expression of the PTEN/PI3K/AKT pathway.

RESULTS

We found that VIP therapy in NOD mice could increase the expression of PTEN and VIP/VPAC1 receptor, as well as decrease the PI3K/AKT pathway. In vitro, the results showed that the PTEN knockdown decreased the Treg/Th17 ratio and enhanced the phosphorylated PI3K/AKT pathway, which were reversed with VIP treatment.

CONCLUSIONS

VIP exerts potential therapeutic action in SjD by upregulating PTEN through the PI3K/AKT pathway and Treg/Th17 cell balance.

"Drying effect" of fructus aurantii components and the mechanism of action based on network pharmacology and in vitro pharmacodynamic validation

Background: Fructus aurantii (FA) is the dried, unripe fruit of the plant Citrus aurantium L. and its cultivated varieties. We investigated the drying effect of FA components and how this drying affect is achieved. Methods: We employed systems pharmacology to predict the components and targets of FA that produce its drying effect. These predictions were verified by computer simulation and animal experiments. In the latter, we measured the bodyweight, water consumption, urine output, fecal water content, rate of salivary secretion, and cross-sectional area of the long axis of the submandibular gland of mice. Immunohistochemistry was used to measure expression of aquaporin (AQP)5 in the submandibular gland, AQP2 in the kidney, and AQP3 in the colon. ELISA kits were used to measure the horizontal variation of cyclic adenosine monsophosphate (cAMP), cyclic guanosine monophosphate (cGMP) and interferon-γ. Results: Sixty-seven potentially active components of FA were screened out. FA could produce a drying effect after regulating 214 targets through 66 active components. A total of 870 gene ontology (GO) terms and 153 signaling pathways were identified. The hypoxia inducible factor-1 signaling pathway, phosphoinositide 3-kinase-protein kinase B (PI3K-AKT) signaling pathway, calcium signaling pathway, and Ras signaling pathway may have important roles in the drying effect of FA. Four components of FA were identified: sinensetin, tangeretin, 5-demethylnobiletin and chrysin. These four components could increase the serum level of interferon-γ and ratio of cyclic adenosine monophosphate:cyclic guanosine monophosphate in mice, and affect their water consumption, urine output, fecal water content and rate of salivary secretion. Conclusion: Four components of FA (tangeretin, sinensetin, chrysin, 5-Demethylmobiletin) were closely related to the Janus kinase-signal transducer and activator of transcription-3 (JAK-STAT3), PI3K-AKT, and the other signaling pathways. They can regulate the protein expression of JAK2, STAT3, PI3K, lymphocyte cell-specific protein-tyrosine kinase, vascular endothelial growth factor A, and protein kinase B1, affect water metabolism in the body and, finally, result in a drying effect.

CXCL9, 10, 11/CXCR3 Axis Contributes to the Progress of Primary Sjogren's Syndrome by Activating GRK2 to Promote T Lymphocyte Migration

Primary Sjogren's syndrome (pSS) is a systemic autoimmune disease that causes dysfunction of secretory glands and the specific pathogenesis is still unknown. The CXCL9, 10, 11/CXCR3 axis and G protein-coupled receptor kinase 2 (GRK2) involved in many inflammation and immunity processes. We used NOD/Ltj mice, a spontaneous SS animal model, to elucidate the pathological mechanism of CXCL9, 10, 11/CXCR3 axis promoting T lymphocyte migration by activating GRK2 in pSS. We found that CD4 + GRK2, Th17 + CXCR3 was apparently increased and Treg + CXCR3 was significantly decreased in the spleen of 4W NOD mice without sicca symptom compared to ICR mice (control group). The protein levels of IFN-γ, CXCL9, 10, 11 increased in submandibular gland (SG) tissue accompanied by obvious lymphocytic infiltration and Th17 cells overwhelmingly infiltrated relative to Treg cells at the sicca symptom occurs, and we found that the proportion of Th17 cells was increased, whereas that of Treg cells was decreased in spleen. In vitro, we used IFN-γ to stimulate human salivary gland epithelial cells (HSGECs) co-cultured with Jurkat cells, and the results showed that CXCL9, 10, 11 was increased by IFN-γ activating JAK2/STAT1 signal pathway and Jurkat cell migration increased with the raised of cell membrane GRK2 expression. HSGECs with tofacitinib or Jurkat cells with GRK2 siRNA can reduce the migration of Jurkat cells. The results indicate that CXCL9, 10, 11 significantly increased in SG tissue through IFN-γ stimulating HSGECs, and the CXCL9, 10, 11/CXCR3 axis contributes to the progress of pSS by activating GRK2 to promote T lymphocyte migration.

The NOD Mouse Beyond Autoimmune Diabetes

Autoimmune diabetes arises spontaneously in Non-Obese Diabetic (NOD) mice, and the pathophysiology of this disease shares many similarities with human type 1 diabetes. Since its generation in 1980, the NOD mouse, derived from the Cataract Shinogi strain, has represented the gold standard of spontaneous disease models, allowing to investigate autoimmune diabetes disease progression and susceptibility traits, as well as to test a wide array of potential treatments and therapies. Beyond autoimmune diabetes, NOD mice also exhibit polyautoimmunity, presenting with a low incidence of autoimmune thyroiditis and Sjögren's syndrome. Genetic manipulation of the NOD strain has led to the generation of new mouse models facilitating the study of these and other autoimmune pathologies. For instance, following deletion of specific genes or via insertion of resistance alleles at genetic loci, NOD mice can become fully resistant to autoimmune diabetes; yet the newly generated diabetes-resistant NOD strains often show a high incidence of other autoimmune diseases. This suggests that the NOD genetic background is highly autoimmune-prone and that genetic manipulations can shift the autoimmune response from the pancreas to other organs. Overall, multiple NOD variant strains have become invaluable tools for understanding the pathophysiology of and for dissecting the genetic susceptibility of organ-specific autoimmune diseases. An interesting commonality to all autoimmune diseases developing in variant strains of the NOD mice is the presence of autoantibodies. This review will present the NOD mouse as a model for studying autoimmune diseases beyond autoimmune diabetes.

Integrated Network Pharmacology and Mice Model to Investigate Qing Zao Fang for Treating Sjögren's Syndrome

Sjögren's syndrome (SS) is an autoimmune disease, and its conventional treatment has exhibited limited therapeutic efficacy. Qing Zao Fang (QZF), a traditional Chinese medicine formula, is used in the treatment of Sjögren's syndrome, but its chemical composition is complex, and its pharmacological mechanism is not clear. Therefore, this study aims to explore the potential mechanism of QZF in the treatment of Sjögren's syndrome based on network pharmacology and SS mouse model. The main active components and predicted targets of QZF were analyzed by network pharmacology. The SS mouse model was constructed and divided into 6 groups: control, SS, SS + hydroxychloroquine (HCQ)-treated, SS + low-dose QZF-treated, SS + medium-dose QZF-treated, and SS + high-dose QZF-treated group. Immunohistochemical, ELISA, and qRT-PCR assays were performed to detect the expressions of targets associated with SS. TUNEL staining was used to detect apoptosis. Cumulatively, 230 active compounds and 1883 targets of QZF were identified. There were 227 common targets for QZF and SS. The effective active ingredients were stigmasterol, neocryptotanshinone II, neotanshinone C, miltionone I, and beta-pinene. It mainly acts on biological processes such as inflammatory response, chemokine metabolic process, and immune response as well as pathways such as FoxO signaling pathway, Yersinia infection, HIF-1 signaling pathway, and TNF signaling pathway. In SS mice, levels of AKT1, HIF-1α, TNF-α, IL-6, and IL-17A were increased, while decreased after QZF treatment. In contrast, IL-10 levels were decreased in SS mice and increased in QZF-treated mice. In addition, QZF reduced apoptosis in the submandibular gland tissue compared to SS mice. It can be concluded that the QZF in treatment of SS is the result of the combined action of multiple components, multiple targets, and multiple pathways. This study improves the understanding of the link between QZF and SS on molecular mechanisms.

Tetrahedral Framework Nucleic Acids Reestablish Immune Tolerance and Restore Saliva Secretion in a Sjögren's Syndrome Mouse Model

As one of the most frequent autoimmune diseases, Sjogren's syndrome (SS) is characterized by overactive lymphocytic infiltration in the exocrine glands, with ensuing dry mouth and dry eyes. Unfortunately, so far, there are no appropriate therapies without causing overall immunosuppression. Tetrahedral framework nucleic acids (tFNAs) were regarded as promising nanoscale materials whose immunomodulatory capabilities have already been verified. Herein, we reveal, for the first time, that tFNAs were utilized to treat SS in female nonobese diabetic (NOD) mice, the animal model used for SS. We proved a 250 nM tFNA treatment was successful in suppressing inflammation and stimulating saliva secretion in NOD mice. Specialised proteins for the secretory function and structure of acinar cells in submandibular glands (SMGs) were restored. It has been the permanent goal for SS treatment to establish immune tolerance and stop disease development. Surprisingly, tFNA treatment guided T cells toward regulatory T cells (Tregs), while suppressing T helper (Th) cell responses. Th cells include Th1, Th17, and follicular helper T (Tfh) cells. Tregs are highly significant in immune tolerance. Inducing Tregs is a promising approach to reestablish immune tolerance. Comparable results were also observed in B cell responses. Reductions in the percentage of germinal center (GC) B cells and plasma cells were detected, and a marked increase in the percentage of regulatory B cells (Bregs) was also noticed. The mechanisms of inducing Tregs may associated with cytokine changes. Changes of T cell subsets, especially changes of Tfh, may influence the differentiation of B cells accordingly. Collectively, our results demonstrated the immunomodulatory capacities of tFNAs once again, which may provide a novel, safe, and effective option for the treatment of SS and other autoimmune diseases.

Labial gland-derived mesenchymal stem cells and their exosomes ameliorate murine Sjögren's syndrome by modulating the balance of Treg and Th17 cells

Background

Sjögren's syndrome (SS) is a chronic, systemic autoimmune disorder characterized by sicca syndrome and/or systemic manifestations. The disease severely affects the health and life of patients, and the treatment of SS has always been a clinical challenge and essentially palliative. Mesenchymal stem cells (MSCs) have been reported to exert immunomodulatory effects and as a potential novel therapeutic strategy for SS. Labial gland-derived MSCs (LGMSCs) are a population of resident stem cells in the labial gland, first isolated by our group. Exosomes released by MSCs contain a large variety of bioactive molecules and considered to function as an extension of MSCs.

Methods

LGMSCs were isolated from patients who were needed surgery to remove the lip mucocele and LGMSCs derived exosomes (LGMSC-Exos) were isolated by ultracentrifugation. The non-obese diabetic (NOD) mice were treated with LGMSCs or LGMSC-Exos by tail vein injection. The saliva flow rate of mice was determined and salivary glands were dissected and stained with hematoxylin and eosin. In vitro, peripheral blood mononuclear cells (PBMCs) from SS patients were cocultured with LGMSCs or LGMSC-Exos. Percentage of T helper 17 (Th17) cells and regulatory T (Treg) cells were determined by flow cytometry. The serum levels of cytokines in NOD mice and in the supernatant of the co-culture system by ELISA.

Results

Treatment with LGMSCs or LGMSC-Exos reduced inflammatory infiltration in the salivary glands, and restored salivary gland secretory function in NOD mice. Importantly, LGMSCs or LGMSC-Exos were demonstrated to inhibit the differentiation of Th17 cells but promote the induction of Treg cells in NOD mice and PBMCs from SS patients in vitro, accompanied by reduced interleukin 17 (IL-17), interferon gamma, and IL-6 levels and enhanced transforming growth factor beta and IL-10 secretion by T cells.

Conclusions

LGMSCs are potential candidates for MSCs-based therapy and LGMSC-Exos might be utilized for establishing a new cell-free therapy against SS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02541-0.

The PI3Kδ inhibitor parsaclisib ameliorates pathology and reduces autoantibody formation in preclinical models of systemic lupus erythematosus and Sjӧgren's syndrome

Dysregulation of phosphoinositide 3-kinase δ (PI3Kδ) signaling pathway has been implicated in the pathogenesis of inflammatory and autoimmune diseases. Parsaclisib (INCB050465) represents a potent and selective PI3Kδ inhibitor, which is being clinically investigated for treatment of autoimmune hemolytic anemia and hematological malignancies. We characterized the potential of parsaclisib to ameliorate autoimmune mechanisms implicated in the pathophysiology of systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). Spontaneous mouse models of SLE and SS were utilized to elucidate the efficacy of orally administered parsaclisib on autoreactive B-cell-mediated antibody-driven disease. Parsaclisib significantly reduced disease symptoms and pathology in three distinct mouse models of SLE. Parsaclisib effectively preserved renal function as measured by glomerular filtration rate, abrogated histopathological evidence of nephritis, modulated discrete immune cell subsets, and decreased anti-dsDNA antibody level. Furthermore, parsaclisib demonstrated efficacy in two spontaneous mouse models of SS. Oral parsaclisib treatment ameliorated the severity of salivary gland inflammation and reduced circulating levels of autoantibodies. Parsaclisib mediated improvement of salivary gland inflammation coincided with reduced B-cell activating cytokine (BAFF) in saliva. Transcriptomic analysis of kidney and salivary gland tissues revealed a downregulation in inflammatory gene expression consistent with PI3Kδ pathway inhibition. Parsaclisib reduced autoreactive B-cells and autoantibody levels, and significantly improved nephritis and salivary gland inflammation. These data provide the scientific rationale for PI3Kδ inhibition as a therapeutic strategy for treatment of B-cell-mediated antibody-driven autoimmune diseases.

Intratracheal Poly(I:C) Exposure Accelerates the Immunological Disorder of Salivary Glands in Sjogren's-Like NOD/ShiLtJ Mice

Evidences have suggested that Sjogren's syndrome (SS) is associated with viral infection. The aim of this study was to investigate the involvement of respiratory viral poly(I:C) in the pathogenesis of SS and potential mechanisms using a SS-like NOD/ShiLtJ (NOD) mouse model. 5-week female NOD mice were intratracheally administered poly(I:C) every other day for 5 times to mimic viral infection. Pilocarpine induced saliva secretion was determined every 8 days. Submandibular glands (SMG) and lungs were harvested for the detection of pathological changes. We found that intratracheal administration of poly(I:C) significantly advanced and enhanced the reduction of saliva flow rate in NOD mice. Furthermore, poly(I:C) treatment aggravated the histopathological lesions and inflammatory cells infiltration in SMG. Accompanied by elevated expression of IFN cytokines and IL-33, Th1 activation was enhanced in SMG of poly(I:C)-treated NOD mice, but Th17 cells activation was unchanged among the groups. In addition, intratracheal poly(I:C) exposure promoted the expression of IL-33 and increased T cells proportion in the lung, which were consistent with the change in SMG. Therefore, intratracheal poly(I:C) exposure aggravated the immunological and function disorder of SMG in NOD mice.

The effect of total glucoside of paeony on gut microbiota in NOD mice with Sjögren's syndrome based on high-throughput sequencing of 16SrRNA gene

Purpose

To investigate the effect of total glucoside of paeony (TGP) on gut microbiota in NOD mice with Sjögren’s syndrome (SS), using high-throughput sequencing of 16SrRNA gene.

Methods

Twenty-four NOD mice were randomly assigned to 4 groups (n = 6 per group): sham group receiving deionized water (0.4 ml), hydroxychloroquin group receiving hydroxychloroquin (0.4 ml), TGP group receiving TGP (0.4 ml), and TGP + hydroxychloroquin group receiving 0.4 ml TGP and 0.4 ml hydroxychloroquin. Balb/c mice (n = 6) receiving 0.4 ml deionized water were used as a control group. After intragastric injection of drugs for 8 weeks, feces were collected for high-throughput sequencing of 16SrRNA gene.

Results

The sequencing of 16SrRNA gene resulted in 3686 OTUs, and 10 phyla and 69 genera were identified. Compared with the control group, the indices of Chao, Ace and Shannon in the other 4 groups were significantly lower (P < 0.05), and the Simpson index were significantly higher in the TGP, hydroxychloroquine, and sham groups (P < 0.05). Compared with the sham group, the indices of Chao, Ace and Shannon were significantly higher (P < 0.05), whereas the Simpson index was significantly lower (P < 0.05) in the TGP and TGP + hydroxychloroquine groups. At phylum level, Bacteroidetes was least abundant (36.1%), and Firmicutes was most abundant (56.28%) in the TGP + hydroxychloroquine group. Compared with the other 4 groups, Bacteroidetes was significantly less abundant (P < 0.05) and Firmicutes was significantly more abundant (P < 0.05) in the TGP + hydroxychloroquine group. Verrucomicrobia was most abundant (12.26%) in the hydroxychloroquine, and was significantly more abundant compared with the other 3 groups (P < 0.05). At genus level, compared with the control group, the abundance of Lactobacillus and Incertae of Phylum Firmicutes and Desulfovibrio of Phylum Proteobacteria was significantly increased, and the abundance of Bacteroides and Alloprevotella of Phylum Bacteroidetes and Pseudoflavonifractor of Phylum Firmicutes was significantly decreased in the TGP + hydroxychloroquine group (P < 0.05). Compared with the hydroxychloroquine group, the abundance of Akkermansia of Phylum Verrucomicrobia was significantly decreased in the TGP and TGP + hydroxychloroquine groups (P < 0.05). The abundance of Alistipes of Phylum Bacteroidetes and Desulfovibrio of Phylum Proteobacteria was significantly increased in the TGP + hydroxychloroquine group (P < 0.05).

Conclusions

TGP increases the growth of many key beneficial bacteria, inhibits the growth of dominant pathogenic bacteria, and increases the diversity and abundance of gut microorganisms, especially when combined with hydroxychloroquine. Our findings suggest that TGP may be effective to treat SS by improving the microecological structure of the gut.