Flare-up of cytokines in rheumatoid arthritis and their role in triggering depression: Shared common function and their possible applications in treatment (Review)

Trans-Chalcone (1-3-diphenyl-2-propen-1-one) as a Therapeutic Candidate in Joint Inflammation via Reduction of TNF-α, IL-1β, IL-6, and IL-17 in Rodents: An In Vivo Study by RT-PCR and ELISA analysis

Autoimmune disorders include vast and distinct illnesses and are characterized by an immune system-mediated attack on the body's own tissues. Because of their ability to impact any portion of the body, their clinical symptoms are incredibly varied. The variations in symptoms are normally linked with the release and activation of vasoactive, chemotactic substances and cytokines. Cytokines perform a multitude of vital biological tasks, such as immune response control, inflammation, proliferation, and tissue repair. The reversal of inflammatory cytokines and leukocyte infiltration into the inflamed tissue by natural compounds provides an effective remedy for autoimmune diseases. Here, the oral administration of trans-chalcone (TC) for 28 days was tested with gradually increasing doses (30, 60, and 120 mg/kg) in complete Freund's adjuvant (CFA)-provoked joint tissue stiffness in rats. Paw edema, arthritic index, joint stiffness, thermal and flexion pain, C-reactive protein, and rheumatoid factor (RF) levels were determined to check the tested drug effectiveness in a chronic inflammatory model. Molecular docking studies revealed strong binding affinity with inflammatory cytokines and mediators such as TNF-α, IL-17, COX-2, and iNOS; further, they were quantified at the mRNA level by RT-PCR and ELISA analysis. Oral administration of TC significantly ameliorated paw edema, thymus and spleen indices, joint stiffness, thermal and flexion pain, C-reactive protein, RF, mobility, and stance of the treated animals. This therapeutic effectiveness was linked with a reduction in the mRNA expression of proinflammatory cytokines such as IL-1β, IL-6, and IL-17. The findings of the reported research confirmed the effectiveness of TC in ameliorating joint stiffness and flexion pain by prominently lowering the inflammatory cytokines.

The 5' untranslated region variant rs3811050 C/T of the interleukin-38 encoding gene is associated with susceptibility to rheumatoid arthritis in Iraqi women

BACKGROUND

Interleukin (IL)-38, the latest member of the IL-1 cytokine family, is proposed to have a pathogenic role in rheumatoid arthritis (RA). It is encoded by the IL1F10 gene, which harbors single nucleotide polymorphisms (SNPs) that may predict the risk of autoimmune diseases. Among them are 5' untranslated region (UTR) SNPs, which play a key role in post-transcriptional control, but have not been studied in Iraqi RA patients.

METHODS

Two novel IL1F10 5'UTR SNPs (rs3811050 C/T and rs3811051 T/G) were explored in RA and control women (n = 120 and 110, respectively). SNPs were genotyped using TaqMan assay. An ELISA kit was used to measure serum IL-38 concentrations.

RESULTS

A reduced risk of RA was associated with rs3811050 T allele and CT genotype (corrected probability [pc] = 0.01 and < 0.001, respectively), while there was no significant association with rs3811051. Haplotype analysis demonstrated that C-T haplotype was associated with a 1.65-fold greater risk of RA, whereas a reduced risk was linked to T-G haplotype. IL-38 concentrations were higher in patients than in controls (p < 0.001). In addition, IL-38 showed acceptable performance in distinguishing between RA and control women (p < 0.001). When IL-38 concentrations were stratified according to SNP genotypes, no significant differences were found.

CONCLUSIONS

The rs3811050 variant was more likely to affect RA susceptibility in Iraqi women, and the T allele may play a role in reducing disease risk. IL-38 concentrations were elevated in RA patients, but were not affected by the rs3811050 and rs3811051 genotypes.

Serum PYCARD may become a new diagnostic marker for rheumatoid arthritis patients

BACKGROUND

The objective of this investigation is to analyze the levels and clinical relevance of serum PYCARD (Pyrin and CARD domain-containing protein, commonly known as ASC-apoptosis-associated speck-like protein containing a caspase activation and recruitment domain), interleukin-38 (IL-38), and interleukin-6 (IL-6) in individuals afflicted with rheumatoid arthritis (RA).

METHODS

Our study comprised 88 individuals diagnosed with RA who sought medical attention at the Affiliated Hospital of Chengde Medical University during the period spanning November 2021 to June 2023, constituting the test group. Additionally, a control group of 88 individuals who underwent health assessments at the same hospital during the aforementioned timeframe was included for comparative purposes. The study involved the assessment of IL-38, IL-6, PYCARD, anti-cyclic citrullinated peptide antibody (anti-CCP), and erythrocyte sedimentation rate (ESR) levels in both groups. The research aimed to explore the correlations and diagnostic efficacy of these markers, employing pertinent statistical analyses for comprehensive evaluation.

RESULTS

The test group had higher expression levels of PYCARD, IL-6, and IL-38 than the control group (P < 0.05). Based on the correlation analysis, there was a strong relationship between PYCARD and IL-38 (P < 0.01). The receiver operating characteristic (ROC) curve analysis revealed area under the curve (AUC) values of 0.97, 0.96, and 0.96 when using combinations of PYCARD and anti-CCP, IL-38 and anti-CCP, and IL-6 and anti-CCP for predicting RA, respectively. Importantly, all three of these pairs demonstrated superior AUC values compared to PYCARD, IL-38, IL-6, ESR, or anti-CCP used as standalone diagnostic indicators.

CONCLUSION

PYCARD, IL-6, and IL-38 exhibit promising potential as novel diagnostic markers and may constitute valuable tools for supporting the diagnosis of RA.

Effects of antioxidant vitamins (A, D, E) and trace elements (Cu, Mn, Se, Zn) administration on gene expression, metabolic, antioxidants and immunological profiles during transition period in dromedary camels

BACKGROUND

Nutrition has a primary role for optimum expression of genetic potential, and most of the farmers have limited resources of green fodder. Hence, a fat-soluble vitamin, especially vitamin A and E and trace elements remained most critical in the animal's ration and affects their productive and reproductive performance adversely. Animals cannot be able to produce these vitamins in their bodies; hence, an exogenous regular supply is needed to fulfil the physiological needs and to maintain high production performance. This study elucidated effects of antioxidant vitamins (A, D, E) and trace elements (Cu, Mn, Se, Zn) administration on gene expression, metabolic, antioxidants and immunological parameters in dromedary camels during transition period.

RESULTS

At 0 day, there were no appreciable differences in the expression patterns of the metabolic (IGF-I, ACACA, SCD, FASN, LPL, and BTN1A1) genes between the control and treatment groups, despite lower levels. A substantial variation in the mRNA levels of SOD1, SOD3, PRDX2, PRDX3, PRDX4, PRDX6, and AhpC/TSA was observed between the control and treatment groups, according to the antioxidant markers. In comparison to the control group, the treatment group displayed a significant up-regulation at 0 and 21 days. The treatment and control groups exhibited substantial differences in the mRNA values of IL-1α, IL-1β, IL-6, and TNFα, as indicated by immunological markers. In comparison to the control group, there was a noticeable down-regulation in the treatment group at 0 and + 21 days. But IL10 produced the opposite pattern. No significant difference was observed in glucose, cholesterol, triglyceride, HDL, total protein, NEFA, BHBA, cortisol and IGF-1 levels between control and treatment group. The activity of serum GPx, SOD and TAC was significantly affected by time and treatment x time in supplemented groups as compared with control group. IL-1, IL-1, IL-6, and TNF were noticeably greater in the control group and lower in the treatment group. Additionally, in all groups, the concentration of all pro-inflammatory cytokines peaked on the day of delivery and its lowest levels showed on day 21 following calving. The IL-10 level was at its peak 21 days prior to calving and was lowest on calving day.

CONCLUSION

The results demonstrated a beneficial effect of antioxidant vitamins and trace elements on the metabolic, antioxidant and immunological markers in dromedary camels throughout their transition period.

Upregulation of proBDNF/p75NTR signaling in immune cells and its correlation with inflammatory markers in patients with major depression

ProBDNF is the precursor protein of brain-derived neurotrophic factor (BDNF) expressed in the central nervous system and peripheral tissues. Previous studies showed that the blood levels of both proBDNF and p75 neurotrophic receptors (p75NTR) in major depressive disorder (MDD) were increased, but which blood cell types express proBDNF and its receptors is not known. Furthermore, the relationship between proBDNF/p75NTR and inflammatory cytokines in peripheral blood of MDD is unclear. Peripheral blood mononuclear cells (PBMCs) and serum were obtained from depressive patients (n = 32) and normal donors (n = 20). We examined the expression of proBDNF and inflammatory markers and their correlative relationship in patients with major depression. Using flow cytometry analysis, we examined which blood cells express proBDNF and its receptors. Finally, the role of proBDNF/p75NTR signal in inflammatory immune activity of PBMCs was verified in vitro experiments. Inflammatory cytokines in PBMC from MDD patients were increased and correlated with the major depression scores. The levels of IL-1β and IL-10 were also positively correlated with the major depression scores, while the levels of TNF-α and IL-6 were negatively correlated with the major depression scores. Intriguingly, the levels of sortilin were positively correlated with IL-1β. Q-PCR and Western blots showed proBDNF, p75NTR, and sortilin levels were significantly increased in PBMCs from MDD patients compared with that from the normal donors. Flow cytometry studies showed that proBDNF and p75NTR were present mainly in CD4+ and CD8+ T cells. The number of proBDNF and p75NTR positive CD4+ and CD8+ T cells from MDD patients was increased and subsequently reversed after therapeutic management. Exogenous proBDNF protein or p75ECD-Fc treatment of cultured PBMC affected the release of inflammatory cytokines in vitro. ProBDNF promoted the expression of inflammatory cytokines, while p75ECD-Fc inhibited the expression of inflammatory cytokines. Given there was an inflammatory response of lymphocytes to proBDNF, it is suggested that proBDNF/p75NTR signaling may upstream inflammatory cytokines in MDD. Our data suggest that proBDNF/p75NTR signaling may not only serve as biomarkers but also may be a potential therapeutic target for MDD.

Association between Proinflammatory Cytokines and Anxiety and Depression Symptoms in Rheumatoid Arthritis Patients: A Cross-sectional Study

Background

Rheumatoid arthritis (RA) patients have a greater prevalence of anxiety and depression. Proinflammatory cytokines are elevated in RA. We aim to evaluate the association between systemic inflammation in RA and anxiety and depression.

Methods

There were 31 RA patients, 16 with active disease activity and 15 in remission state; they were assessed using the Hospital Anxiety and Depression Scale and for RA disease activity using Disease Activity Score of 28 joints (DAS28) - CRP (C-reactive protein). Serum proinflammatory cytokines were measured, including interleukin (IL)-6, IL-17, and Tumour Necrosis Factor-alpha (TNF-α).

Results

Among 31 patients, ten patients showed anxiety symptoms, 19 patients showed depression symptoms, and two displayed mixed symptoms. Serum TNF-α levels were significantly higher in active disease than in the remission group (p-value 0.006). There was no association or correlation between proinflammatory cytokines to anxiety and depression symptoms in the active disease and remission groups.

Conclusion

This suggests that other factors besides disease activity and state of systemic inflammation may cause anxiety and depression in RA patients.

Causal association of juvenile idiopathic arthritis-associated uveitis with depression and anxiety: a bidirectional Mendelian randomization study

PURPOSE

The objective of this article was to examine the potential effect of juvenile idiopathic arthritis-associated uveitis (JIAU) on the risk of major depressive and anxiety disorders through Mendelian randomization (MR) study.

METHODS

Genetic instrumental variables from the largest available genome-wide association study for JIAU, major depressive disorder, and anxiety disorder were applied. A set of complementary MR approaches including inverse-variance weighted (IVW) were carried out to verify the estimate association and assess horizontal pleiotropy.

RESULTS

Our results indicated that genetically driven JIAU did not causally produce changes in major depressive or anxiety disorders (IVW: OR = 1.001, 95% CI = 0.997-1.006, P = 0.581; IVW: OR = 1.006, 95% CI = 0.980-1.033, P = 0.649, respectively). In addition, the risk of JIAU could not be influenced by genetically predicted major depressive or anxiety disorders (IVW: OR = 1.132, 95% CI = 0.914-1.404, P = 0.256; IVW: OR = 1.019, 95% CI = 0.548-1.896, P = 0.953, respectively). Besides, several sensitivity analyses indicated that our MR results were robust and no horizontal pleiotropy was observed (P > 0.05).

CONCLUSIONS

Our MR study does not reveal sufficient evidence to support the causal association of JIAU with the development of major depressive or anxiety disorders in both directions. Further large studies are warranted to validate the undetermined relationship between JIAU and the risk of major depressive or anxiety disorders.

Exploration of acute and chronic anti-inflammatory potential of Quercus leucotrichophora A. Camus extracts in Wistar rats: A mechanistic insight

Introduction: This research was conducted to validate the folkloric use of Quercus leucotrichophora (QL) leaf extracts against inflammation and arthritis and to determine the chemical composition using HPLC. Method: The aqueous and methanolic extracts of QL were evaluated by in vitro anti-oxidant, anti-inflammatory (inhibition of protein denaturation and membrane stabilization) assays, and in vivo anti-inflammatory (carrageenan and xylene-induced edema) and anti-arthritic models. For anti-arthritic potential, 0.1 mL Complete Freund's Adjuvant (CFA) was inoculated into the left hind paw of a Wistar rat on day 1, and oral dosing with QL methanolic extract (QLME) at 150, 300, and 600 mg/kg was begun at day 8 till the 28th day in all groups, except disease control that was given distilled water, while methotrexate was given as standard treatment. Results and discussion: There was a noteworthy (p < 0.05-0.0001) restoration in body weight, paw edema, arthritic index, altered blood parameters, and oxidative stress biomarkers in treated rats as compared to the diseased group. Moreover, QLME treatment significantly (p < 0.0001) downregulated TNF-α, IL-6, IL-1β, COX-2, and NF-κB, while significantly (p < 0.0001) upregulating IL-10, I-κB, and IL-4 in contrast to the diseased group. The QLME exhibited no mortality in the acute toxicity study. It was concluded that QLME possessed substantial anti-oxidant, anti-inflammatory, and anti-arthritic potential at all dosage levels prominently at 600 mg/kg might be due to the presence of quercetin, gallic, sinapic, and ferulic acids.

Depression in Rheumatoid Arthritis: A Narrative Review-Diagnostic Challenges, Pathogenic Mechanisms and Effects

Depression is one of the most frequent comorbidities in rheumatoid arthritis (RA); it takes an important toll on the quality of life of these patients and also leads to a decrease in life expectancy. The current article is a narrative review on depression in RA, with the objective to emphasize and raise awareness on the high prevalence, pathogenic mechanisms, and effects that depression has on RA patients. In RA, the prevalence of depression has been shown to be 2 to 3 times higher than in the general population, with a meta-analysis reporting that 16.8% of RA patients have a major depressive disorder. Future studies are needed to determine the most accurate self-reported depression questionnaires and their ideal threshold for defining depression as compared to diagnostic interview as gold-standard for patients with RA to allow better comparisons across studies. The pathogenesis of depression remains to be fully understood, but recent specialty literature suggests that immune-mediated processes are involved and that there are similarities between the neural networks recruited in inflammation and those implicated in the pathophysiology of depression. Depression in patients with RA is associated with poor long-term outcomes. Multiple studies have shown that depression in RA is associated with increased pain, fatigue, and physical disability. It alters treatment compliance, causes more comorbidities, and leads to higher mortality, partly through increased suicide risk. Depression in RA also increases health service utilization and healthcare costs directly through hospitalization, but also indirectly through loss of work productivity. Assessing depression could be a significant psychomarker of rheumatological outcome in RA.

3D Cell Culture as Tools to Characterize Rheumatoid Arthritis Signaling and Development of New Treatments

Rheumatoid arthritis (RA) is one of the most common autoimmune disorders affecting 0.5-1% of the population worldwide. As a disease of multifactorial etiology, its constant study has made it possible to unravel the pathophysiological processes that cause the illness. However, efficient and validated disease models are necessary to continue the search for new disease-modulating drugs. Technologies, such as 3D cell culture and organ-on-a-chip, have contributed to accelerating the prospecting of new therapeutic molecules and even helping to elucidate hitherto unknown aspects of the pathogenesis of multiple diseases. These technologies, where medicine and biotechnology converge, can be applied to understand RA. This review discusses the critical elements of RA pathophysiology and current treatment strategies. Next, we discuss 3D cell culture and apply these methodologies for rheumatological diseases and selected models for RA. Finally, we summarize the application of 3D cell culture for RA treatment.

A Systematic Review of Nutritional Interventions on Key Cytokine Pathways in Rheumatoid Arthritis and Its Implications for Comorbid Depression: Is a More Comprehensive Approach Required?

Rheumatoid arthritis (RA) is associated with both local and systemic inflammatory processes via the aberrant regulation of inflammatory pathways and imbalances in several mediators of inflammation. Cytokines, tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1B, IL-6, IL-17, IL-18, rheumatoid factor, anti-cyclic citrullinated protein, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) have been used in diagnosing and tracking the progression of RA. The primary objective of this review is to identify and summarize which specific dietary patterns and nutritional interventions go beyond symptom management to improve the response to known inflammatory cytokines and possibly decrease markers of inflammation in the RA disease process. Analysis of the 41 identified publications demonstrated that certain dietary patterns, the consumption of specific macronutrients, and supplementation with herbals or other compounds have shown some effect on improving cytokine profiles in patients with RA.

This review illustrates the importance of proper patient education on the anti-inflammatory and potential protective impacts substantial dietary change may have on the disease progression and symptoms of RA. Identifying nutritional interventions and dietary patterns that improve the inflammatory cytokine profile, and therefore disease progression and inflammatory comorbidities of RA will help further focus research on treatments that may provide a better overall improvement in quality of life for RA patients by focusing on the root cause inflammatory processes that affect not only joint destruction but also depression-rated disability. This review further notes that while depression is commonly found in patients who suffer from chronic illnesses, it is especially prevalent in the RA population. The pathology of depression is associated with systemic inflammation, which is a known outcome of RA and may explain this strong association. Cytokines IL-6, IL-1, and TNF-α, known mediators involved in the progression of RA, are strongly associated with stress-related disorders including depression and anxiety. The presence of these cytokines is also correlated with the severity and duration of depression. This may signal a potential use of cytokines in diagnosing and following the progression of depression not only in patients with RA but also others. Given the statistics presented on depression and suicide in patients with RA, and the shared inflammatory pathway between the two diseases, depression and suicide screening scales should be included along with analysis of inflammatory markers and disease activity scores (DAS) in any future RA study.

The role of C5a-C5aR1 axis in bone pathophysiology: A mini-review

Bone remodeling is a physiological, dynamic process that mainly depends on the functions of 2 cell types: osteoblasts and osteoclasts. Emerging evidence suggests that complement system is crucially involved in the regulation of functions of these cells, especially during inflammatory states. In this context, complement component 5a (C5a), a powerful pro-inflammatory anaphylatoxin that binds the receptor C5aR1, is known to regulate osteoclast formation and osteoblast inflammatory responses, and has thus been proposed as potential therapeutic target for the treatment of inflammatory bone diseases. In this review, we will analyze the role of C5a-C5aR1 axis in bone physiology and pathophysiology, describing its involvement in the pathogenesis of some of the most frequent inflammatory bone diseases such as rheumatoid arthritis, and also in osteoporosis and bone cancer and metastasis. Moreover, we will examine C5aR1-based pharmacological approaches that are available and have been tested so far for the treatment of these conditions. Given the growing interest of the scientific community on osteoimmunology, and the scarcity of data regarding the role of C5a-C5aR1 axis in bone pathophysiology, we will highlight the importance of this axis in mediating the interactions between skeletal and immune systems and its potential use as a therapeutic target.

Assessment of IL-1β, IL-6, TNF-α, IL-8, and CCL 5 levels in newly diagnosed Saudi patients with rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disorder which mainly affects small joints, occurs most commonly in middle-aged adults, and can be fatal in severe cases. The exact etiology of RA remains unknown. However, uncontrolled expression of pro-inflammatory cytokines and chemokines can contribute to the pathogenesis of RA.

AIM

In the current study, we assessed the potential of serum concentrations of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, IL-8, and C-C motif chemokine ligand (CCL)5 as early predictive markers for RA.

METHODS

In addition to clinical examination, blood samples were collected from 100 Saudi patients recently diagnosed with early RA for basic and serological tests, including rheumatoid factor (RF), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). Sera of 32 healthy individuals were used as controls. Specific enzyme-linked immunosorbent assay was used to quantify the serum IL-1β, IL-6, TNF-α, IL-8, and CCL5 levels in the samples.

RESULTS

Our results indicated that RF, CRP, and ESR levels were higher in RA patients compared to controls. Furthermore, serum levels of IL-1β, IL-6, IL-8, and CCL5, but not TNF-α, significantly increased in RA patients compared to controls.

CONCLUSION

Overall, the findings suggested that IL-1β, IL-6, IL-8, and CCL5 can be used as biomarkers in the early diagnosis of RA.

Cytokines and chemokines multiplex analysis in patients with low disease activity rheumatoid arthritis

Rheumatoid arthritis is a severe chronic autoimmune disorder that results from pathological activation of immune cells and altered cytokine/chemokine network. The aim of our study was to evaluate concentrations of chosen cytokines and chemokines in blood sera and synovial fluid samples isolated from low disease activity rheumatoid arthritis (RA) patients and osteoarthritis (OA) sufferers. Blood sera and synovial fluid samples have been obtained from 24 OA and 14 RA patients. Cytokines/chemokines levels have been determined using a Milliplex^® Map 38-plex human cytokine/chemokine magnetic bead-based panel (Merck Millipore, Germany) and Luminex^® MAGPIX^® platform (Luminex USA). Low disease activity RA patients showed altered concentration of numerous cytokine/chemokine when compared to OA controls—they were characterized by, inter alia, increased: eotaxin/CCL11 (p = 0.037), GRO/CXCL1 (p = 0.037), IL-2 (p = 0.013), IL-4 (p = 0.017), IL-7 (p = 0.003), IL-8 (p = 0.0007) and GM-CSF (p = 0.037) serum levels, whilst MDC/CCL22 concentration was decreased in this group (p = 0.034). Eotaxin/CCL11 (p = 0.001), GRO/CXCL1 (p = 0.041), IL-10 (p = 0.003), GM-CSF (p = 0.01), IL-1RA (p = 0.0005) and VEGF (p = 0.01) concentrations in synovial fluid of RA females were also increased. Even with low disease activity score, RA patients exhibited increased concentrations of cytokines with pro- and anti-inflammatory activities, as well as numerous chemokines, growth factors and regulators of angiogenesis. Surprisingly, RA subjects also shown decreased concentration of CCL22 chemokine. The attempt to restore cytokine balance and tolerogenic environment is ineffective in RA sufferers even with good disease management. Distinguished factors could serve as possible indicators of disease progression even in low disease activity patients.

proBDNF/p75NTR promotes rheumatoid arthritis and inflammatory response by activating proinflammatory cytokines

P75 pan-neurotrophin receptor (p75NTR) is an important receptor for the role of neurotrophins in survival and death of neurons during development and after nerve injury. Our previous research found that the precursor of brain-derived neurotrophic factor (proBDNF) regulates pain as an inflammatory mediator. The current understanding of the role of proBDNF/p75NTR signaling pathway in inflammatory arthritis pain and rheumatoid arthritis (RA) is unclear. We recruited 20 RA patients, 20 healthy donors (HDs), and 10 osteoarthritis (OA) patients. Hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) of proBDNF and p75NTR in synovial membrane were performed and evaluated. We next examined the mRNA and protein expression of proBDNF/p75NTR signaling pathway in peripheral blood mononuclear cells (PBMCs) and synovial tissue. ELISA and flow cytometry were assessed between the blood of RA patients and HD. To induce RA, collagen-induced arthritis (CIA) were induced in mice. We found over-synovitis of RA synovial membrane compared to OA controls in histologic sections. P75NTR and sortilin mRNA, and proBDNF protein level were significantly increased in PBMCs of RA patients compared with the HD. Consistently, ELISA showed that p75NTR, sortilin, tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10) levels in the serum of RA patients were increased compared with HD and p75NTR, sortilin were positively correlated with Disease Activity Score in 28 joints (DAS28). In addition, using flow cytometry we showed that the increased levels of proBDNF and p75NTR characterized in CD4⁺ and CD8⁺ T cells of RA patients were subsequently reversed with methotrexate (MTX) treatment. Furthermore, we found pathological changes, inflammatory pain, upregulation of the mRNA and protein expression of proBDNF/p75NTR signaling pathway, and upregulation of inflammatory cytokines in spinal cord using a well-established CIA mouse model. We showed intravenous treatment of recombinant p75ECD-Fc that biologically blocked all inflammatory responses and relieved inflammatory pain of animals with CIA. Our findings showed the involvement of proBDNF/p75NTR pathway in the RA inflammatory response and how blocking it with p75ECD-Fc may be a promising therapeutic treatment for RA.

Curcumin and Mesenchymal Stem Cells Ameliorate Ankle, Testis, and Ovary Deleterious Histological Changes in Arthritic Rats via Suppression of Oxidative Stress and Inflammation

Rheumatoid arthritis (RA) is a chronic inflammatory condition, an autoimmune disease that affects the joints, and a multifactorial disease that results from interactions between environmental, genetic, and personal and lifestyle factors. This study was designed to assess the effects of curcumin, bone marrow-derived mesenchymal stem cells (BM-MSCs), and their coadministration on complete Freund's adjuvant- (CFA-) induced arthritis in male and female albino rats. Parameters including swelling of the joint, blood indices of pro-/antioxidant status, cytokines and histopathological examination of joints, and testis and ovary were investigated. RA was induced by a single dose of subcutaneous injection of 0.1 mL CFA into a footpad of the right hind leg of rats. Arthritic rats were treated with curcumin (100 mg/kg b.wt./day) by oral gavage for 21 days and/or treated with three weekly intravenous injections of BM-MSCs (1 × 10⁶ cells/rat/week) in phosphate-buffered saline (PBS). The treatment with curcumin and BM-MSCs singly or together significantly (P < 0.05) improved the bioindicators of oxidative stress and nonenzymatic and enzymatic antioxidants in sera of female rats more than in those of males. Curcumin and BM-MSCs significantly (P < 0.05) improved the elevated TNF-α level and the lowered IL-10 level in the arthritic rats. Furthermore, joint, testis, and ovary histological changes were remarkably amended as a result of treatment with curcumin and BM-MSCs. Thus, it can be concluded that both curcumin and BM-MSCs could have antiarthritic efficacies as well as protective effects to the testes and ovaries which may be mediated via their anti-inflammatory and immunomodulatory potentials as well as oxidative stress modulatory effects.

USP2-Related Cellular Signaling and Consequent Pathophysiological Outcomes

Ubiquitin specific protease (USP) 2 is a multifunctional deubiquitinating enzyme. USP2 modulates cell cycle progression, and therefore carcinogenesis, via the deubiquitination of cyclins and Aurora-A. Other tumorigenic molecules, including epidermal growth factor and fatty acid synthase, are also targets for USP2. USP2 additionally prevents p53 signaling. On the other hand, USP2 functions as a key component of the CLOCK/BMAL1 complex and participates in rhythmic gene expression in the suprachiasmatic nucleus and liver. USP2 variants influence energy metabolism by controlling hepatic gluconeogenesis, hepatic cholesterol uptake, adipose tissue inflammation, and subsequent systemic insulin sensitivity. USP2 also has the potential to promote surface expression of ion channels in renal and intestinal epithelial cells. In addition to modifying the production of cytokines in immune cells, USP2 also modulates the signaling molecules that are involved in cytokine signaling in the target cells. Usp2 knockout mice exhibit changes in locomotion and male fertility, which suggest roles for USP2 in the central nervous system and male genital tract, respectively. In this review, we summarize the cellular events with USP2 contributions and list the signaling molecules that are upstream or downstream of USP2. Additionally, we describe phenotypic differences found in the in vitro and in vivo experimental models.