Taneja, Veena

Abstract Rheumatoid arthritis (RA) is a chronic disease involving inflammation of the joints. While the etiology of RA remains unknown, evidence exists for a significant contribution of the major histocompatibility complex (MHC). Environmental factors are also indicated as playing an etiological role. Since it is impossible to define the mechanisms contributing to disease onset and progression in humans, mouse models have been used widely. While many animal models have been generated by immunization with self‐proteins to induce arthritis, type II collagen (CII)‐induced arthritis is one of the most commonly used models utilized to understand the immunopathology of RA. CII constitutes 80% to 90% of total collagen content of hyaline cartilage found in joints and is a genetically conserved sequestered protein. Immunization with heterologous CII with an adjuvant in mice leads to cellular and humoral responses to heterologous and autoreactive CII‐specific responses and collagen‐induced arthritis (CIA). Mice immunized with CII develop inflammatory arthritis that shares many similarities in clinical, serological, and radiological features with RA in humans. However, selecting an antigen for inducing arthritis and the mouse strain are important, as not all strains are susceptible to CIA. A critical difference between RA and CIA is that in mice that lack the expression of human MHC II, the development of CIA is linked to the H2A locus, which is the homologue of HLA‐DQ, while most human studies have linked RA susceptibility with HLA‐DR alleles. Mice expressing HLA‐DQ and HLA‐DR molecules have been used to understand the role of MHC genes in susceptibility to RA. The protocols for inducing CIA in the HLA expressing transgenic mice described in this article can be used to understand how the different HLA molecules confer susceptibility to RA. © 2025 Wiley Periodicals LLC. Basic Protocol 1 : Use of mouse strains and humanized mice for modeling rheumatoid arthritis Basic Protocol 2 : Use of humanized mice for therapeutic protocols

Abstract Description Antigen receptor (CAR) T cells can be generated in vivo within the natural lymph node (LN) environment as the immune response to a virus infection unfolds. This in situ approach entails priming LNs with intradermal inoculations of replication defective adenoviruses encoding MHC class I and class II allo/xeno-antigens. Universal transplant antigens were devised for LN priming by introducing tryptophan into amino acid position 162 of the MHC HLA-A2:01 class I heavy chain and by using the mouse MHC class II beta chain to form chimeric class II antigens with endogenous class II alleles. The virus encoded mismatched MHC antigen presenting molecules are expressed functionally in the LN following intradermal inoculation provoking polyclonal T cells responses. Three days later CAR T cells are generated by directly injecting retroviruses encoding CARs of interest into the responding LN. Mouse CD19-specifc CAR T cells created in this manner in B6-DQ8 and DQ8/A2 mice effectively target endogenous B cells and are therapeutic in male and female Emu-myc lymphomas demonstrating the potential for the generating functional CAR T cells directly in vivo. While in situ CAR T cells are readily produced in B6, B6-IA0/DQ8, B6-IA0/DQ8/A2, and B6-IA0/DQ6 LNs, functional differences among the strains emerged in the periphery suggesting that properties of the autoimmune-associated HLA DQ8 class II allele is particularly reactive during the production of CAR T cells in vivo. Funding Sources MustangBio, Inc Mayo Clinic Center of Biomedical Research Mayo Clinic Department of Immunology Mayo Clinic Graduate School of Biomedical Science Fraternal Order of Eagles Mayo Clinic Ventures NIH R21 AI 097337 NIH R01 CA 178804 NIH T32 AI 07425 Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)

Rheumatoid arthritis (RA) is an autoimmune disease with an unknown etiology. While certain genes provide strong susceptibility factors, the role of environmental factors is becoming increasingly recognized. Among genetic factors, human leukocyte antigen (HLA) genes, encoded within the major histocompatibility complex (MHC), have been linked to predisposition to RA, while among environmental factors, smoking, infections and diet are the major contributors. Genetic and environmental factors impact microbial composition in the host. Based on the dysbiosis observed in the gut and lung microbiome, a mucosal origin of RA has been suggested. However, proving whether genes or microbes provide a stronger risk factor has been difficult. Studies from RA patients and various mouse models, specifically humanized mice expressing HLA class II genes, have been instrumental in defining the role of environmental factors such as smoking and endogenous small intestinal microbes in modulating arthritis severity. The consensus based on most studies support an interaction between host genetic and environmental factors in the onset and severity of disease. However, until now, no microbial markers for disease prognosis or treatment efficacy have been available. Here, the role of gut microbes as markers of disease severity, and the potential for using endogenous commensals for modulating immune responses to suppress inflammation in the context of genetic factors, are discussed.

SummaryRheumatoid arthritis (RA) is considered a multifactorial condition where interaction between the genetic and environmental factors lead to immune dysregulation causing autoreactivity. While among the various genetic factors, HLA‐DR4 and DQ8, have been reported to be the strongest risk factors, the role of various environmental factors has been unclear. Though events initiating autoreactivity remain unknown, a mucosal origin of RA has gained attention based on the recent observations with the gut dysbiosis in patients. However, causality of gut dysbiosis has been difficult to prove in humans. Mouse models, especially mice expressing RA‐susceptible and ‐resistant HLA class II genes have helped unravel the complex interactions between genetic factors and gut microbiome. This review describes the interactions between HLA genes and gut dysbiosis in sex‐biased preclinical autoreactivity and discusses the potential use of endogenous commensals as indicators of treatment efficacy as well as therapeutic tool to suppress pro‐inflammatory response in rheumatoid arthritis.

Although the etiology of rheumatoid arthritis (RA) is unknown, a strong genetic predisposition and the presence of preclinical antibodies before the onset of symptoms is documented. An expansion of Eggerthella lenta is associated with severe disease in RA. Here, using a humanized mouse model of collagen-induced arthritis, we determined the impact of E. lenta abundance on RA severity. Naïve mice gavaged with E. lenta produce preclinical rheumatoid factor and, when induced for arthritis, develop severe disease. The augmented antibody response was much higher in female mice, and among patients with RA, women had higher average load of E. lenta . Expansion of E. lenta increased CXCL5 and CD4 T cells, and both interleukin-17– and interferon-γ–producing B cells. Further, E. lenta gavage caused gut dysbiosis and decline in amino acids and nicotinamide adenine dinucleotide with an increase in microbe-dependent bile acids and succinyl carnitine causing systemic senescent-like inflammation.

Abstract DRB1*0401 has been associated with predisposition to rheumatoid arthritis while DRB1*0402 is associated with resistance. We have generated transgenic mice lacking endogenous H2-A and E molecules (AEo) but expressing DRB1*0401 or DRB1*0402 molecules. All transgenic mice expressed functional DR molecules which could positively and negatively select various Vβ T cell repertoire profile. Transgenic mice were studied in vivo for induction of arthritis following immunization with type II collagen. DRB1*0401 mice are susceptible to collagen-induced arthritis while DRB1*0402 mice are resistant. Presence of DR4 leads to arthritis predominantly in female mice. CIA susceptible AEo.DQ8 mice have been shown to develop arthritis without a gender bias. However, AEo mice expressing DRB1*0401.DQ8 develop arthritis in female mice with a ratio of 3F:1M, similar to that in humans. DRB1*0402 mice did not show any defect in humoral response though they demonstrated a lower cellular response to CII and an increased activation-induced cell death compared to susceptible mice. In vitro T cell response with superantigen staphylococcal enterotoxin B and Concovalin A showed that DRB1*0402 mice are not defective in generating T cell response. The resistant mice showed an increased cell death in thymus suggesting deletion of autoreactive T cells at thymic level might be one reason for protection. The data suggest that DRB1 polymorphism lead to selection of TCR in thymus thus controlling the selection of autoreactive T cells available in periphery. Thus these transgenic mice may be useful to study the reasons for gender-bias observed in human patients develop therapeutic strategies.

Abstract We have previously shown that treatment with a novel human commensal, Prevotella histicola, isolated from a duodenal biopsy, can protect HLA-DQ8 mice from collagen induced arthritis (CIA), a model for RA, by modulating the systemic immune response. The present study analyzed the functional and mechanistic impact of P. histicola by comparing pain, motor function, gut microbiota and metabolites in treated and non-treated arthritic DQ8 mice. P. histicola treatment reduced the arthritis-associated pain by improving the motor function when compared to control mice. Analysis of synovium showed that P. histicola treatment increased T regulatory cells and reduced the levels of IL6 in the synovium of arthritic mice which were associated with reduced pain. Treated mice showed P. histicola colonization in the duodenum, a niche from where it was isolated. Further, P. histicola treatment showed varied effects based on circadian rhythm. A longitudinal follow-up of the gut microbial profile in different gut sections suggested that dysbiosis caused due to arthritis in DQ8 is partly normalized to naïve profile after treatment with P. histicola. Treated mice showed an expansion of genus Allobaculum, a butyrate-producing Firmicutes in the guts of DQ8 arthritic mice as compared to pre-treatment. The post-treatment restoration was also reflected in short-chain fatty acids and glucose assimilation rates in T cells. The present study proposes that P. histicola treatment of arthritis in DQ8 mice leads to gut homeostasis. Normalized microbial diversity and metabolites lead to immune regulation resulting in reduced inflammation with improved physical function. The observations suggest P. histicola as a strong candidate for monoclonal bio-therapeutics.

Abstract Rheumatoid arthritis (RA) occurs twice more often in women than men. B cell depletion has been shown to be efficacious in treating RA though it is unknown if efficacy is dependent on the sex of the patient. Our previous studies suggested that antigen presentation via B cells results in a sex-specific immune response and cytokines in humanized mice. Now we show that the efficacy of B cell depletion in arthritic DQ8 mice is sex-dependent. Arthritic female DQ8 mice treated with anti-CD20 antibody in therapeutic protocols show milder disease severity associated with decreased antibodies to citrullinated proteins along with increased numbers of T regulatory as compared to male DQ8 mice. The milder disease severity in CD20-depleted females was associated with reduced levels of IL-23 and CCL5 with increased IL-13 as compared to males. Treated male mice showed higher numbers of subsets of dendritic cells, known producers of pro-inflammatory cytokines, as compared to females. A window where males can benefit from B cell depletion needs to be defined. Our observations suggest that in therapeutic strategies that target B cells during established disease may benefit females while DCs might be relatively more important for men than women.

Abstract While the etiology of rheumatoid arthritis (RA) is unknown, both genetic and environmental factors are involved in pathogenesis. Among genetic factors, HLA-DRB1*0401/DQ8 provide the strongest association. Among environmental factors, Cigarette smoking (CS) has been associated with a 2-fold increase in risk for developing seropositive RA; specially individuals carrying DRB1*0401 who smoke cigarettes. It has been hypothesized that the response to Vimentin precedes the onset of RA. To determine the interaction between genetic factors and CS, we generated transgenic mice expressing RA-susceptible DRB1*0401 and DQ8 genes in the absence endogenous class II molecules. To determine how cigarette smoke (CS) interacts with host genetic factors in the induction of RA-associated autoimmunity, we used transgenic mice carrying the RA-susceptible HLA genes DR4 and DQ8, but lacking all endogenous murine class II molecules. Cigarette smoke exposure augmented immune responses to citrullinated synovial antigens, collagen and vimentin. Interestingly, CS exposure suppressed collagen-induced arthritis (CIA) in DRB1*0401 mice even though innate immune response was enhanced. On the other hand, CS exposure exacerbated CIA in DQ8 mice, which was accompanied by an increased expression of Th17 gene transcripts in lungs. These observations suggest that cigarette smoke promotes antigen-specific autoimmunity that is profoundly influenced by host genetic factor.