Chondrocytes are responsible for producing and maintaining the extracellular matrix of cartilage, whose proteins undergo changes under inflammatory conditions observed in join diseases. Several reports have shown that animal venoms display immunomodulatory and anti-inflammatory effects in arthritis models. Animal venoms are characterized by the unique biochemical diversity of their toxins and the repertoire of cellular receptors and signaling pathways they target to fulfill their role in poisoning. This opens new perspectives for the discovery of of new targets for therapeutic intervention in inflammatory joint diseases. Lonomia obliqua caterpillar venom is well-known to cause a hemorrhagic syndrome and systemic proinflammatory response in patients that become in contact with its urticating’s bristles. Lopap and Losac are both cytoprotective proteins derived from L. obliqua bristles extract (LOCBE). In this context, the aim of this study was to determine if LOCBE and recombinant Lopap and Losac are able to modulate ECM lost under inflammatory conditions induced by interleukin 1β in chondrocytes. Both molecules were able to reduce the loss of ECM proteins involved in tissue remodeling (as collagen) and to preserve substrate attachment and ECM integrity. LOCBE was able to increase the mitochondrial activity with no effect on NF-kB pathway. However, LOCBE increased the expression of nuclear MMP-1, a well-known collagenase with an important role in apoptosis and ECM remodeling. Analysis of chondrocytes with Lopap and Losac revealed that Lopap induced the higher expression of nuclear MMP-1 and increased mitochondrial activity. Thus, MMP-1 could be an important target being modulated by LOCBE and the recombinant proteins and related to their cytoprotective effects widely studied. We demonstrated that LOCBE and recombinant proteins Lopap and Losac are important sources for the study of cytoprotection, apoptosis and the mechanism of nuclear MMP-1, which is no longer a well-understood process. Further studies must be performed to elucidate the biological relevance of this effect in the envenoming, and if there are, other pathways activated without the involvement of the NF-kB pathway.

Rheumatoid arthritis (RA) patients have double incidence of heart failure with preserved ejection fraction (HFpEF), a risk that may augment with current treatments, including glucorticoids and anti-TNF therapies. New models and targets are required to address this unmet clinical need [PMID: 36041475]. The KBxN F1 mouse colony develops arthritis prior to develop diastolic dysfunction: these animals respond to the pro-resolving therapeutic with human recombinant Annexin A1 [PMID: 34526398]. Herein, we targeted IL-6 and Galectin-3 (Gal-3), since both these mediators were elevated in KBxN F1 mice prior to cardiac alterations. Treatment of male and female mice (n=10 per group) with anti-IL-6 receptor antibody (MR16-1) from week 6 to week 12, significantly i) prevented the increase of the left atrium area (LAA) by ~10% and ii) improved the E/A ratio and E’/A’ wave ratio (p<0.05 in both cases). Ejection fraction did not vary among the experimental groups. MR16-1 reduced arthritic score and paw oedema by ~15% as compared to the vehicle group. Functional cardiac changes were associated with lower recruitment of Ly6Chi CRR2+ monocytes to the heart at week 12, together with lower pro-inflammatory fibroblast numbers (p<0.05). Finally, treatment of mice with MR16-1 significantly reduced the expression of Gal-3+ in cardiac macrophages (MHCII+). Since Gal-3 is a pro-fibrotic protein which circulating levels increase in KBxN F1 mouse plasma over the disease timeline, the effect of a Gal-3 inhibitor (GB1107) was then tested. Daily administration of GB1107 (10 mg/kg orally; week 6-12), did not affect the arthritic score nor paw oedema. Similarly to MR16-1, the Gal-3 inhibitor GB1107 reduced LAA enlargement by ~12% and improved the E/A ratio and E’/A’ ratio. In summary, KBxN F1 transgenic mice develop diastolic dysfunction and this experimental model can be used to elucidate mechanistic alterations in the heart as well as allow testing of effecrtive therapeutic approaches. Our ultimate goal is to prevent development of HFpEF in RA patients, a pathology markedly ignored by current treatment regimens. MC is funded by Chernajovsky Foundation and William Harvey Research Foundation. JC is a career-development fellow of Versus Arthritis UK. The generous donation of MR16-1 by Genentech Corp. (CA, USA) is acknowledged.

The aim of this study was to perform an in-depth investigation of the transcriptome of systemic lupus erythematosus (SLE) patients with active central nervous system (CNS) involvement to gain insights into underlying molecular mechanisms and identify new potential drug targets for CNS lupus. We analysed dysregulated gene modules in peripheral blood from patients with active CNS lupus (n=26) and active non-neuropsychiatric (NP) SLE (n=43) versus healthy controls (n=497) from the European PRECISESADS project (NTC02890121). Gene modules were subjected to correlation analyses with serological markers, and regulatory network and druggability analysis. Unsupervised co-expression network analysis revealed 23 dysregulated gene modules. Four showed differential dysregulation between two distinct subgroups of CNS lupus patients. The interferon module was upregulated in both subgroups. In silico prediction algorithms demonstrated a greater anticipated response to anifrolumab and calcineurin inhibitors for the active CNS subgroup with B cell, T cell, cytotoxic/NK cell, and mitochondrial gene downregulation compared with the patient subgroup of mixed dysregulation patterns. In this cohort of SLE patients of European origin, B cell, T cell, cytotoxic/NK cell, and mitochondrial gene dysregulation patterns separated active CNS lupus patients into two distinct subgroups with differential anticipated response to type I interferon and calcineurin inhibition. Our study provides a conceptual framework for precision medicine in CNS lupus.

Alterations in the microbiota can potentially contribute to the onset and severity of rheumatoid arthritis (RA). In this study, we investigated whether the hyperactivity of popliteal lymphatic vessels (pLVs) observed in a specific pathogen-free (SPF) mouse model of TNFα-induced arthritis could be mitigated by germ-free (GF) mice within the same model. pLVs were isolated from male TNFΔARE/+ and wild type (WT) SPF and GF 12 week-old mice and mounted on a pressure myograph. Their diameter and contraction frequency (CF) were then measured in response to a stepwise increase in transmural pressure. Effects of the non-selective NOS inhibitor (L-NNA, 100 µmol/l) was evaluated. To confirm inflammation in the TNFΔARE mice, popliteal lymph nodes (pLN) were collected for myeloperoxidase activity (MPO) assessment. RA was evaluated using the Laboras. Results were analyzed by multiple t-test and two-way ANOVA followed by Tukey’s test. Pressure myography showed a significant increase in pLV CF (min-1, SPF: 16.2±3.3 vs 8.5±0.5; GF: 11.2±1.2 vs 9.0±0.5, P<0.05) and diastolic diameter (µm, SPF 110.3±3.8 vs 97.3±8.1; GF 113.1±4.4 vs 90.7±7.9, P<0.05) in TNFΔARE/+ mice compared WT. In the presence of L-NNA, the differences in diameters were abolished, while the CF was increased (min-1, 11.0±3.9 vs 6±1.1, P<0.05) only in SPF arthritis mice. MPO activity was increased in TNFΔARE/+ pLN compared to WT (U/mg, SPF: 0.009±0.001 vs. 0.0005±0.0002; GF: 0.005±0.002 vs. 0.0004±0.00004, P<0.0001). Furthermore, Laboras test showed significant decrease in climbing activity (counts, SPF: 9.5±4.5 vs. 279.5±9.9; GF: 33.5±12.2 vs. 298.1 ±55.7, P<0.05) in TNFΔARE/+ mice compared WT. In summary, our findings confirm that the microbiota does not play a role in the joint-pLV-pLN axis in the development of arthritis but is a factor that worsens the disease. Furthermore, the potential influence of TNF-α on the inflammatory process appears to be associated with changes in the eNOS-NO pathway within the popliteal lymphatic vessel in mice with spontaneous arthritis.

In rheumatoid arthritis (RA), various molecular factors contribute to disease progression. Platelet-derived extracellular vesicles (PEVs) induce inflammation in synovial fibroblasts, while ferritin serves as a disease activation biomarker. The autotaxin (ATX) pathway exacerbates inflammation, particularly bone erosions. Phosphatidylserine (PS), mediated by phosphatidylserine-specific phospholipase A1A (PLA1A), perpetuates inflammatory cascades. However, the existing literature lacks comprehensive information, with only one study addressing the proteome composition of red blood cell (RBC)-derived vesicles (REVs). We conducted a two-year assessment on 79 early arthritis (EA) patients and 30 age-sex-matched healthy controls. Blood parameters were analyzed via ELISA and FACS, including normality tests, non-parametric tests, correlation analyses, Principal Component Analysis, and Partial Least Squares. EA patients, with a mean baseline age of 59.14±12.41 years, showed significantly elevated PAC+ platelets, CD62+ platelets, PAC+CD62P+ platelets, ferritin, PS+ PEVs, PS+ RBCs, PS+ REVs, and PLA1A levels compared to controls. Correlation analysis revealed significant associations between ATX and ferritin, PAC+ platelets and ferritin, PAC+ platelets and PS+ RBCs, CD62P+ and ferritin, CD62P+ platelets and PS+ REVs, PAC+CD62P+ platelets and ferritin, and PAC+CD62P+ platelets andPS+ RBCs. Over two years, EA patients exhibited increased ATX, PLA1A, and PS+ PEV levels, whereas ferritin and PS+ REVs decreased. PAC+ platelets, CD62+ platelets, PAC+CD62P+ platelets, and PS+ RBCs exhibited fluctuations over the study period in EA patients. A significant association was found between PS+ PEVs at two years and new plaque formation. Notably, treatment did not impact platelet activation markers and EV levels. This study reveals significant fluctuations in blood biomarkers associated with EA. Elevated levels of platelet activation markers, ferritin, and PLA1A in EA patients underline their association with the disease. Over the study period, dynamic changes were observed, including increases in ATX, PLA1A and PS+PEVs, alongside decreases in ferritin and PS+ REVs, suggesting their potential as disease activity indicators. The association between PS+ PEVs and increased plaque formation risk accentuates their clinical relevance.