AbstractRetinitis pigmentosa (RP) is characterized by progressive photoreceptor cells death accelerated by the proliferation and activation of microglia pathologically. No consensus exists on the treatment. Minocycline is recognized as a microglia inhibitor with great anti-inflammatory and neuro-protective functions. However, efficacy of minocycline in RP patients is lacking. We conducted a prospective, open-label, and single-arm trial, in which daily oral minocycline of 100 mg was administered for 12 months in RP patients with light-adapted 30 Hz flicker electroretinography (ERG) amplitude >0 µV in at least one eye (NCT04068207). The primary outcome was the proportion of participants with improvement in the ERG amplitude at month 12. The secondary outcomes included improvements of the following items: other ERGs amplitudes, visual field, best-corrected visual acuity, contrast sensitivity, color vision, and NEI-VFQ-25. 35 of 288 patients met inclusive criteria were enrolled (median [IQR] age, 36 [31–45] years; 17 female [48.6%]). 32 participants completed all examinations, while 3 participants completed the 12-month online visit via conducting NEI-VFQ-25. The primary outcome showed improvement was 34.3% (12 of 35 [95% CI 19.1–52.2]). Similarly, all secondary outcomes showed improvements. Adverse events were reported in 22 participants (62.9%) and were all resolved without extra medication during the study period. No severe adverse events were recorded. Our findings identified daily oral minocycline of 100 mg for 12 months was beneficial in improving the visual function of RP patients with good safety. This study indicates minocycline may be a promising therapy for RP, but a randomized controlled trial is still needed of further exploration.

Abstract Background Thyroid eye disease (TED) is a vision-threatening autoimmune disorder. Orbital tissue fibrosis leading to intractable complications remains a troublesome issue in TED management. Exploration of novel therapeutic targets and agents to ameliorate tissue fibrosis is crucial for TED. Recent work suggests that Ca2+ signaling participates in tissue fibrosis. However, whether an alteration of Ca2+ signaling has a role in fibrogenesis during TED remains unclear. In this study, we aimed to investigate the role of Ca2+ signaling in the fibrogenesis process during TED and the potential therapeutic effects of a highly selective inhibitor of the L-type calcium channel (LTCC), nimodipine, through a TGF-β1 induced in vitro TED model. Methods Primary culture of orbital fibroblasts (OFs) were established from orbital adipose connective tissues of patients with TED and healthy control donors. Real-time quantitative polymerase chain reaction (RT-qPCR) and RNA sequencing were used to assess the genes expression associated with LTCC in OFs. Flow cytometry, RT-qPCR, 5-ethynyl-2′-deoxyuridine (EdU) proliferation assay, wound healing assay and Western blot (WB) were used to assess the intracellular Ca2+ response on TGF-β1 stimulation, and to evaluate the potential therapeutic effects of nimodipine in the TGF-β1 induced in vitro TED model. The roles of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and signal transducer and activator of transcription 1 (STAT1) in fibrogenesis during TED were determined by immunohistochemistry, WB, flow cytometry and co-immunoprecipitation assay. Selective inhibitors were used to explore the downstream signaling pathways. Results LTCC inhibitor nimodipine blocked the TGF-β1 induced intracellular Ca2+ response and further reduced the expression of alpha-smooth muscle actin (α-SMA), collagen type I alpha 1 (Col1A1) and collagen type I alpha 2 (Col1A2) in OFs. Besides, nimodipine inhibited cell proliferation and migration of OFs. Moreover, our results provided evidence that activation of the CaMKII/STAT1 signaling pathway was involved in fibrogenesis during TED, and nimodipine inhibited the pro-fibrotic functions of OFs by down-regulating the CaMKII/STAT1 signaling pathway. Conclusions TGF-β1 induces an LTCC-mediated Ca2+ response, followed by activation of CaMKII/STAT1 signaling pathway, which promotes the pro-fibrotic functions of OFs and participates in fibrogenesis during TED. Nimodipine exerts potent anti-fibrotic benefits in vitro by suppressing the CaMKII/STAT1 signaling pathway. Our work deepens our understanding of the fibrogenesis process during TED and provides potential therapeutic targets and alternative candidate for TED.

Minocycline, a broad-spectrum tetracycline antibiotic, has been shown to possess anti-inflammatory and antioxidative effects in various neurodegenerative diseases. However, its specific effects on retinitis pigmentosa (RP) have not been thoroughly investigated. Therefore, the objective of this study was to explore the potential role of minocycline in treating RP. In this investigation, we used rd1 to explore the antioxidant effect of minocycline in RP. Minocycline therapy effectively restored retinal function and structure in rd1 mice at 14 days postnatal. Additionally, minocycline inhibited the activation of microglia. Moreover, RNA sequencing analysis revealed a significant downregulation in the expression of mitochondrial genes within the retina of rd1 mice. Further KEGG and GO pathway analysis indicated impaired oxidative phosphorylation and electron transport chain processes. TEM confirmed the presence of damaged mitochondria in photoreceptors, while JC-1 staining demonstrated a decrease in mitochondrial membrane potential, accompanied by an increase in mitochondrial reactive oxygen species (ROS) levels. However, treatment with minocycline successfully reversed the abnormal expression of mitochondrial genes and reduced the levels of mitochondrial ROS, thereby providing protection against photoreceptor degeneration. Collectively, minocycline demonstrated the ability to rescue photoreceptor cells in RP by effectively modulating mitochondrial homeostasis and subsequently inflammation. These findings hold significant implications for the development of potential therapeutic strategies for RP.

PURPOSE. Experimental autoimmune uveitis (EAU) is a representative animal model of human uveitis. In this study, we investigated whether apolipoprotein A1 (APOA1) can alleviate EAU and explored its underlying mechanism. METHODS. Mice were immunized with interphotoreceptor retinoid-binding protein 1-20 and treated with APOA1 or vehicle. The retinas, draining lymph nodes (DLNs), and spleens were analyzed. Isolated T cells were used for proliferation, differentiation, and function assays in vitro. Selective inhibitors and pathway agonists were used to study signaling pathways. The effect of APOA1 on peripheral blood mononuclear cells (PBMCs) from uveitis patients was also examined. RESULTS. Administration of APOA1 ameliorated EAU. APOA1 suppressed pathogenic CD4+ T cell expansion in DLNs and spleen, and decreased the infiltration of effector T (Teff) cells into retina. APOA1 also inhibited T cell proliferation and T helper 1 cell differentiation in vitro and promoted regulatory T (Treg) cell differentiation. APOA1 restricted inflammatory cytokine production from lipopolysaccharide-stimulated PBMCs. Mechanistic studies revealed that the effect of APOA1 was mediated by scavenger receptor class B type I (SR-BI) and downstream signals including phosphatidylinositol 3-kinase/Protein kinase B (PKB, or Akt), p38 mitogen-activated protein kinase, and nuclear factor-kappa B. CONCLUSIONS. APOA1 ameliorates EAU by regulating the Teff/Treg partially through SR-BI. Our results suggest that APOA1 can be a therapeutic alternative for autoimmune uveitis.

PurposeInflammation triggers the activation of CD4+T cells and the breakdown of blood–retinal barrier, thus contributing to the pathology of experimental autoimmune uveitis (EAU). We explored the anti-inflammatory effect of hydroxychloroquine (HCQ) on EAU and the potential mechanisms active in T cells and retinal vascular endothelial cells (RVECs).MethodsC57BL/6J mice were immunized with interphotoreceptor retinoid binding protein 1-20 (IRBP1–20) to induce EAU and then treated with the vehicle or HCQ (100 mg/kg/day). On day 7, 14, 21, 30 and 60 after immunization, clinical scores were evaluated. On day 14, histopathological scores were assessed, and retinas, spleens, and lymph nodes were collected for quantitative polymerase chain reaction or flow cytometry analysis. RVEC dysfunction was induced by tumor necrosis factor α (TNF-α) stimulation. The expression of cytokines, chemokines, adhesion molecules, and lectin-like oxidized LDL receptor-1 (LOX-1)/nuclear factor κB (NF-κB) was measured in RVECs with or without HCQ.ResultsHCQ treatment protected mice from uveitis, evidenced by reduced expression of inflammatory factors, chemokines, and adhesion molecules in the retina. In systemic immune response, HCQ inhibited the activation of naïve CD4+T cells and frequencies of T effector cells, and promoted T regulatory cells. HCQ decreased IRBP1-20–specific T cell responses and proliferation of CD4+T cells in vitro. Further studies established that TNF-α induced RVECs to express inflammatory cytokines, chemokines, and adhesion molecules, whereas HCQ alleviated the alterations via the LOX-1/NF-κB pathways.ConclusionsHCQ alleviates EAU by regulating the Teff/Treg balance and ameliorating RVECs dysfunction via the LOX-1/NF-κB axis. HCQ may be a promising therapeutic candidate for uveitis.

IL-23/IL-23R and PGE2/EP2+EP4 have been recognized as crucial signals that promote Th17 differentiation in many autoimmune diseases, including thyroid-associated ophthalmopathy (TAO). However, the interactive role of IL-23R in IL-23/Th17 signaling and PGE2/Th17 signaling has not been clarified in TAO. Furthermore, the role of IL-38, a novel anti-inflammatory cytokine, has not been explored in TAO. Thus, we aimed to investigate the roles of IL-23R and IL-38 in the pathogenesis of TAO. Activated peripheral blood mononuclear cells (PBMCs) were cultured with or without IL-23 and PGE2. The results showed that IL-23R and IL-17A were upregulated to different degrees and reached the highest levels with both stimuli, indicating that IL-23 induced PBMCs to secrete PGE2, which further boosted the proportion of IL-23R+CD4+T cells to promote IL-17A secretion. Pretreatment with antagonists aimed at EP2/EP4 receptors diminished PGE2-induced upregulation of IL-23R and IL-17A. IL-38 in TAO patients was increased. Activated orbital fibroblasts (OFs) and PBMCs were pretreated with different concentrations of IL-38. IL-23R and IL-17A expression in circulating PBMCs and IL-6 and IL-8 in resident OFs were suppressed by IL-38 at relatively low concentrations. Our findings suggest that the feedback loop of IL-23/IL-23R/PGE2/EP2+EP4/IL-23R/IL-17A plays a significant role in the pathogenesis of TAO and that IL-23R is one of the key targets. Increased IL-38 in TAO could not only inhibit the expression of IL-23R and IL-17A in PBMCs but also suppress inflammation in OFs. Therapies targeting IL-23R may be effective, and IL-38 could be a potential therapeutic approach for TAO.