Proteomic analysis of CHIKV-infected human fibroblast-like synoviocytes: Identification of host factors potentially associated with CHIKV replication and cellular pathogenesis.

Chikungunya virus (CHIKV) is a mosquito-borne virus that causes arthralgic fever. Fibroblast-like synoviocytes play a key role in joint damage in inflammatory arthritides and can additionally serve as target cells for CHIKV infection. To gain a better understanding of CHIKV-induced arthralgia, the interaction between CHIKV and synoviocytes was investigated at the protein level. A gel-enhanced liquid chromatography-mass spectrometry (GeLC-MS/MS) approach was used to examine protein expression from primary human fibroblast-like synoviocytes (HFLS) infected with clinical isolates of CHIKV at 12 and 24 hr post infection. Our analysis identified 259 and 241 proteins of known function that were differentially expressed (>1.5 or <-1.5 fold change) following CHIKV infection at 12 and 24 hpi, respectively. These proteins are involved in cellular homeostasis, including cellular trafficking, cytoskeletal organization, immune response, metabolic process, and protein modification. Some of these proteins have previously been reported to participate in arthralgia/arthritis and the death of infected cells. Our results provide information on the CHIKV-induced modulation of cellular proteins of HFLS at an early stage of infection, as well as highlighting biological processes associated with CHIKV infection in the main target cells of the joint.

DPP-4 INHIBITORS INCREASE THE INCIDENCE OF ARTHRITIS/ARTHRALGIA BUT DO NOT AFFECT AUTOIMMUNITY.

AIMS: In August 2015, FDA published a black box declaring that DPP-4 inhibitors may cause severe joint pains. The impact on autoimmunity marker positivity of these drugs has not been comprehensively evaluated. We compared the incidence of arthritis/arthralgia in patients with T2DM who were using DPP-4 inhibitors and patients who were not using. METHODS: A number of 93 DPP-4 inhibitor users and 107 non-users were included into the study. Arthritis/arthralgia were found in 41 of 93 (44.1%) DPP-4 inhibitor users and in 19 of 107 (17.8%) non-users (p<0.05). RESULTS: No inflammatory rheumatological condition was identified in 27 of 41 (65.9%) patients in DPP-4 inhibitor user group as well as in 13 of 19 (68.4%) patients in non-user group (p>0.05). After adjusting for gender the incidence for arthritis/arthralgia was significantly increased in the DPP-4 inhibitor user group (p value for any DPP-inhibitor <0.05). There was 3.77 times increased risk for arthritis/arthralgia in the DPP-4 inhibitor using group (p value= 0.001) and this risk increases 2.43 times for each year of DPP-4 inhibitor usage. CONCLUSIONS: Arthritis/arthralgia were more common among T2DM patients who were using DPP-4 inhibitors compared to non-users, but the seropositivity did not differ between DPP-4 inhibitor users and non-users.

Rheumatological manifestations in patients hospitalized with COVID-19 in a tertiary care setting.

BACKGROUND: Corona virus disease 2019 (COVID-19) is a pandemic affecting over 150 million people worldwide since its emergence in Wuhan, China in December 2019, and is leading to over 600 thousand deaths. Severe acute respiratory syndrome novel coronavirus 2 (SARS-nCoV-2) causes a wide range of symptoms by affecting different organ systems of the body. This study was designed to specifically look for its rheumatological manifestations. METHODS: It was a cross-sectional study conducted in the corona complex MTI Lady Reading Hospital Peshawar. A total of 141 COVID-19 positive hospitalized patients requiring oxygen therapy and having no previous rheumatological diseases were enrolled and studied for any rheumatological manifestations. RESULTS: There were 88 (62.4%) males and 53 (37.6%) females, with age range from 27-88 years, and mean age of 58.5±11.5 SD. Arthralgia and myalgia were found very common, occurring in 128 (90.8%) and 119 (84.4%) of patients. Arthritis was not found in any patient. CONCLUSION: Arthralgia and myalgia were reported frequently in patients with severe COVID-19 requiring oxygen therapy, while arthritis was not present even in a single patient as is reported in other viral infections.

Functional validation reveals the novel missense V419L variant in TGFBR2 associated with Loeys-Dietz syndrome (LDS) impairs canonical TGF-ß signaling.

TGF-ß-related heritable connective tissue disorders are characterized by a similar pattern of cardiovascular defects, including aortic root dilatation, mitral valve prolapse, vascular aneurysms, and vascular dissections and exhibit incomplete penetrance and variable expressivity. Because of the phenotypic overlap of these disorders, panel-based genetic testing is frequently used to confirm the clinical findings. Unfortunately in many cases, variants of uncertain significance (VUSs) obscure the genetic diagnosis until more information becomes available. Here, we describe and characterize the functional impact of a novel VUS in the TGFBR2 kinase domain (c.1255G>T; p.Val419Leu), in a patient with the clinical diagnosis of Marfan syndrome spectrum. We assessed the structural and functional consequence of this VUS using molecular modeling, molecular dynamic simulations, and in vitro cell-based assays. A high-quality homology-based model of TGFBR2 was generated and computational mutagenesis followed by refinement and molecular dynamics simulations were used to assess structural and dynamic changes. Relative to wild type, the V419L induced conformational and dynamic changes that may affect ATP binding, increasing the likelihood of adopting an inactive state, and, we hypothesize, alter canonical signaling. Experimentally, we tested this by measuring the canonical TGF-ß signaling pathway activation at two points; V419L significantly delayed SMAD2 phosphorylation by western blot and significantly decreased TGF-ß-induced gene transcription by reporter assays consistent with known pathogenic variants in this gene. Thus, our results establish that the V419L variant leads to aberrant TGF-ß signaling and confirm the diagnosis of Loeys-Dietz syndrome in this patient.

Osteoclastogenesis induced by CHIKV-infected fibroblast-like synoviocytes: a possible interplay between synoviocytes and monocytes/macrophages in CHIKV-induced arthralgia/arthritis.

Fibroblast-like synoviocytes are known to migrate from joint to joint and are proposed to be one of the key players in the inflammatory cascade amplification in rheumatoid arthritis patients. In the recent CHIKV epidemic, patients developed arthritis-like syndrome and the synoviocyte is one of the suspected players in CHIKV-induced polyarthritis. Thus, to learn more on this syndrome, the responses of fibroblast-like synoviocytes to chikungunya virus (CHIKV) infection, and the interaction between CHIKV-infected synoviocytes and phagocytes, were investigated. Primary human fibroblast-like synoviocyte (HFLS) cultures were infected with clinical isolates of CHIKV at an MOI of 0.001pfu/cell. Data indicated that HFLS are permissive to CHIKV replication, generating peak titers of 10(5)-10(6)pfu/ml. Interestingly, CHIKV-infected HFLS cultures secreted mainly the mediators that are responsible for phagocytes recruitment and differentiation (RANKL, IL-6, IL-8 and MCP-1) but not arthritogenic mediators (TNF-α, IL-1ß, MMP-1, MMP-2 or MMP-13). The interaction between CHIKV-infected synoviocytes and phagocytes was studied using UV-irradiated, CHIKV-infected HFLS supernatant. Data revealed that supernatants from CHIKV-infected HFLS cultures not only induced migration of primary human monocytes, but also drove monocytes/macrophages into osteoclast-like cells. These differentiated osteoclast-like cells produced high levels of TNF-α and IL-6, principal mediators of arthritis. This data suggests a potential interplay between infected HFLS and recruiting phagocytes which may responsible for the arthralgia/arthritis in CHIKV-infected patients.