Galectin-3: A key player in arthritis

Plasma Proteomic Analysis Based on 4D-DIA Evaluates the Clinical Response to Imrecoxib in the Early Treatment of Osteoarthritis

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the primary treatment for osteoarthritis (OA), but prolonged use has adverse effects and varying efficacy. Among NSAIDs, imrecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, reduces side effects yet remains ineffective for half of the patient population. This study aims to identify biomarkers for early evaluation of imrecoxib efficacy in OA for personalized therapy optimization.

METHODS

From September 2021 to January 2022, imrecoxib was administered to patients with OA at Nanjing Drum Tower Hospital. Plasma samples from these patients underwent proteomic analysis through the four-dimensional data-independent acquisition (4D-DIA) method, followed by bioinformatics analysis. Potential differentially expressed proteins (DEPs) were validated using enzyme-linked immunosorbent assays (ELISA).

RESULTS

Sixty-six patients with knee OA were included and divided into responders (n = 35) and non-responders (n = 31). Proteomic analysis was conducted on 15 patients from each group, with ELISA validation for every patient. We found 140 DEPs between the two groups after imrecoxib treatment, characterized by 29 proteins showing upregulation and 111 displaying downregulation (P < 0.05, fold change >  ± 1.2). Galectin-1 (LGALS1), galectin-3 (LGALS3), and cluster of differentiation 44 (CD44) were identified as potential markers for evaluating clinical response to imrecoxib in OA following ELISA validation.

CONCLUSION

This study successfully identified biomarkers for evaluating imrecoxib's clinical response in patients with OA using 4D-DIA technology. These biomarkers may play a vital role in future personalized OA treatment strategies, pending further confirmation.

Circulating levels of galectin-3 and coronary microvascular perfusion in rheumatoid arthritis patients with suppressed inflammation

OBJECTIVE

Cardiovascular manifestations are the leading cause of mortality in rheumatoid arthritis (RA). Galectin-3, a lectin protein with major role in cellular, inflammatory, and fibrotic processes, has been introduced as a novel cardiac biomarker. We hypothesized that patients with RA present increased levels of galectin-3, and investigated potential associations with arterial stiffness and coronary microvascular dysfunction.

METHODS

This cross-sectional study enrolled RA patients and non-RA individuals without cardiovascular comorbidities. Galectin-3 and high-sensitivity C-reactive protein (hsCRP) were measured with enzyme-linked immunosorbent assay (ELISA) in serum samples. Subendocardial viability ratio (SEVR), an index of microvascular myocardial perfusion, and pulse wave velocity (PWV), the gold-standard measure of vascular stiffness, were estimated with applanation tonometry.

RESULTS

Cardiovascular risk factors and hsCRP were comparable between patients (n = 24) and controls (n = 24). However, galectin-3 was increased [6.9 (6.7) vs 4.6 (4.7)] ng/dl, p = 0.015], and coronary microvascular perfusion was decreased (142.6 ± 22.8 vs 159.7 ± 23.2%, p = 0.028) in RA patients compared to controls, whereas PWV did not significantly differ. Galectin-3 correlated with both PWV and SEVR in univariate analysis. However, after adjustment for cardiovascular risk factors and subclinical inflammation, these associations were rendered non-significant.

CONCLUSION

Galectin-3 appears increased in RA, even among patients with suppressed inflammation in the absence of cardiovascular comorbidities. The observed association of galectin-3 with coronary microvascular perfusion in our study was non-significant after adjustment for cardiovascular risk factors and inflammation. The potential role of galectin-3 as a cardiac biomarker in RA warrants further investigation. Key Points • Galectin-3 has emerged as a novel cardiac biomarker but remains understudied in RA. • Patients with RA present elevated levels of galectin-3 and impaired coronary microvascular perfusion compared to non-RA individuals. • These differences were observed in patients with suppressed inflammation, even in the absence of CVD. • The association of galectin-3 with coronary microvascular impairment in RA warrants further investigation.

Immune regulatory networks coordinated by glycans and glycan-binding proteins in autoimmunity and infection

The immune system is coordinated by an intricate network of stimulatory and inhibitory circuits that regulate host responses against endogenous and exogenous insults. Disruption of these safeguard and homeostatic mechanisms can lead to unpredictable inflammatory and autoimmune responses, whereas deficiency of immune stimulatory pathways may orchestrate immunosuppressive programs that contribute to perpetuate chronic infections, but also influence cancer development and progression. Glycans have emerged as essential components of homeostatic circuits, acting as fine-tuners of immunological responses and potential molecular targets for manipulation of immune tolerance and activation in a wide range of pathologic settings. Cell surface glycans, present in cells, tissues and the extracellular matrix, have been proposed to serve as "self-associated molecular patterns" that store structurally relevant biological data. The responsibility of deciphering this information relies on different families of glycan-binding proteins (including galectins, siglecs and C-type lectins) which, upon recognition of specific carbohydrate structures, can recalibrate the magnitude, nature and fate of immune responses. This process is tightly regulated by the diversity of glycan structures and the establishment of multivalent interactions on cell surface receptors and the extracellular matrix. Here we review the spatiotemporal regulation of selected glycan-modifying processes including mannosylation, complex N-glycan branching, core 2 O-glycan elongation, LacNAc extension, as well as terminal sialylation and fucosylation. Moreover, we illustrate examples that highlight the contribution of these processes to the control of immune responses and their integration with canonical tolerogenic pathways. Finally, we discuss the power of glycans and glycan-binding proteins as a source of immunomodulatory signals that could be leveraged for the treatment of autoimmune inflammation and chronic infection.

Effect of galectin-3 on synovial inflammation in knee osteoarthritis via stimulating phosphatidylinositol-3-kinase/Akt pathway

Galectin-3 (Gal-3), a glycan-binding protein responsible for inflammation, has been reportedly implicated in inflammatory arthritis. This study aimed to determine clinical and pathological effects of Gal-3 on inflammation in knee osteoarthritis (OA). Gal-3 mRNA and protein levels in synoviocytes, synovium, synovial fluid, and plasma of knee OA patients were determined using real-time polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay. Signaling mechanism underlying inflammatory effect of Gal-3 was further elucidated in human knee OA synoviocytes. Clinical study uncovered significant increases in plasma and synovial fluid Gal-3 levels in knee OA patients, particularly those with advanced-stage. In knee OA patients, plasma Gal-3 was significantly associated with radiographic severity and indicators of body composition, physical performance, and knee pain and disability. In the inflamed synovium of knee OA patients, further analysis depicted a marked up-regulation of Gal-3 mRNA expression, consistent with immunohistochemical analysis showing localization of Gal-3 protein in the lining and sublining layers of the inflamed synovium. An in vitro study unveiled that aberrant Gal-3 mRNA expression was regulated by tumor necrosis factor (TNF)-α in knee OA synoviocytes. Gal-3 significantly enhanced production of NO and IL-6, up-regulated mRNA expressions of IL-6, NF-κB, and MMP-13, and down-regulated mRNA expressions of ACAN and SOX-9 via stimulating Akt phosphorylation in knee OA synoviocytes. Gal-3 exerted an inflammatory action, which might emerge as a possible mediator of synovitis and cartilage degeneration in knee OA.

Development of Galectin-3 Targeting Drugs for Therapeutic Applications in Various Diseases

Galectin-3 (Gal3) is one of the most studied members of the galectin family that mediate various biological processes such as growth regulation, immune function, cancer metastasis, and apoptosis. Since Gal3 is pro-inflammatory, it is involved in many diseases that are associated with chronic inflammation such as cancer, organ fibrosis, and type 2 diabetes. As a multifunctional protein involved in multiple pathways of many diseases, Gal3 has generated significant interest in pharmaceutical industries. As a result, several Gal3-targeting therapeutic drugs are being developed to address unmet medical needs. Based on the PubMed search of Gal3 to date (1987-2023), here, we briefly describe its structure, carbohydrate-binding properties, endogenous ligands, and roles in various diseases. We also discuss its potential antagonists that are currently being investigated clinically or pre-clinically by the public and private companies. The updated knowledge on Gal3 function in various diseases could initiate new clinical or pre-clinical investigations to test therapeutic strategies, and some of these strategies could be successful and recognized as novel therapeutics for unmet medical needs.

Computational Fluid Dynamics (CFD) Model for Analysing the Role of Shear Stress in Angiogenesis in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterised by an attack on healthy cells in the joints. Blood flow and wall shear stress are crucial in angiogenesis, contributing to RA's pathogenesis. Vascular endothelial growth factor (VEGF) regulates angiogenesis, and shear stress is a surrogate for VEGF in this study. Our objective was to determine how shear stress correlates with the location of new blood vessels and RA progression. To this end, two models were developed using computational fluid dynamics (CFD). The first model added new blood vessels based on shear stress thresholds, while the second model examined the entire blood vessel network. All the geometries were based on a micrograph of RA blood vessels. New blood vessel branches formed in low shear regions (0.840-1.260 Pa). This wall-shear-stress overlap region at the junctions was evident in all the models. The results were verified quantitatively and qualitatively. Our findings point to a relationship between the development of new blood vessels in RA, the magnitude of wall shear stress and the expression of VEGF.

Galectin-3 interacts with PD-1 and counteracts the PD-1 pathway-driven regulation of T cell and osteoclast activity in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by joint inflammation and bone erosions. The glycosylated programmed death-1 (PD-1) receptor plays an important role in regulating immune responses and maintaining tolerance. In this study, we focus on two features observed in RA: impaired PD-1 signalling and Galectin-3 (Gal-3) upregulation. We hypothesize that Gal-3 binds PD-1 and PD-1 ligands, potentially contributing to impaired PD-1 signalling. PD-1 and Gal-3 levels in RA synovial fluid (SF) and plasma were evaluated by ELISA. PD-1 and Gal-3 interaction was examined by Surface Plasmon Resonance and ELISA. PD-1, PD-L1 and Gal-3 expression on mononuclear cells from SF and peripheral blood as well as fibroblast-like synoviocytes were examined by flow cytometry. Effects of Gal-3 and PD-L1 on osteoclast formation was evaluated by tartrate-resistant acid phosphatase assay. We show that Gal-3 binds PD-1 and PD-L1. Results demonstrated high expression of PD-1 and Gal-3 on mononuclear cells, especially from SF. Gal-3 inhibited PD-1 signalling when PD-L1 was present. Furthermore, a role of Gal-3 in osteoclast formation was observed in vitro, both directly but also through PD-1:PD-L1 inhibition. Effects of Gal-3 on the PD-1 signalling axis are proposed to be inhibitory, meaning high Gal-3 levels in the complex synovial microenvironment are not desirable in RA. Preventing Gal-3's inhibitory role on PD-1 signalling could, therefore, be a therapeutic target in RA by affecting inflammatory T cell responses and osteoclasts.

Increased Galectin-9 Levels Correlate with Disease Activity in Patients with DMARD-Naïve Rheumatoid Arthritis and Modulate the Secretion of MCP-1 and IL-6 from Synovial Fibroblasts

Background: Fibroblast-like synoviocytes (FLSs) are essential mediators in the expansive growth and invasiveness of rheumatoid synovitis, and patients with a fibroblastic-rich pauci-immune pathotype respond poorly to currently approved antirheumatic drugs. Galectin-9 (Gal-9) has been reported to directly modulate rheumatoid arthritis (RA) FLSs and to hold both pro- and anti-inflammatory properties. The objective of this study was to evaluate clinical and pathogenic aspects of Gal-9 in RA, combining national patient cohorts and cellular models. Methods: Soluble Gal-9 was measured in plasma from patients with newly diagnosed, treatment-naïve RA (n = 98). The disease activity score 28-joint count C-reactive protein (DAS28CRP) and total Sharp score were used to evaluate the disease course serially over a two-year period. Plasma and synovial fluid samples were examined for soluble Gal-9 in patients with established RA (n = 18). A protein array was established to identify Gal-9 binding partners in the extracellular matrix (ECM). Synovial fluid mononuclear cells (SFMCs), harvested from RA patients, were used to obtain synovial-fluid derived FLSs (SF-FLSs) (n = 7). FLSs from patients suffering from knee Osteoarthritis (OA) were collected from patients when undergoing joint replacement surgery (n = 5). Monocultures of SF-FLSs (n = 6) and autologous co-cultures of SF-FLSs and peripheral blood mononuclear cells (PBMCs) were cultured with and without a neutralizing anti-Gal-9 antibody (n = 7). The mono- and co-cultures were subsequently analyzed by flow cytometry, MTT assay, and ELISA. Results: Patients with early and established RA had persistently increased plasma levels of Gal-9 compared with healthy controls (HC). The plasma levels of Gal-9 were associated with disease activity and remained unaffected when adding a TNF-inhibitor to their standard treatment. Gal-9 levels were elevated in the synovial fluid of established RA patients with advanced disease, compared with corresponding plasma samples. Gal-9 adhered to fibronectin, laminin and thrombospondin, while not to interstitial collagens in the ECM protein array. In vitro, a neutralizing Gal-9 antibody decreased MCP-1 and IL-6 production from both RA FLSs and OA FLSs. In co-cultures of autologous RA FLSs and PBMCs, the neutralization of Gal-9 also decreased MCP-1 and IL-6 production, without affecting the proportion of inflammatory FLSs. Conclusions: In RA, pretreatment plasma Gal-9 levels in early RA were increased and correlated with clinical disease activity. Gal-9 levels remained increased despite a significant reduction in the disease activity score in patients with early RA. The in vitro neutralization of Gal-9 decreased both MCP-1 and IL-6 production in an inflammatory subset of RA FLSs. Collectively these findings indicate that the persistent overexpression of Gal-9 in RA may modulate synovial FLS activities and could be involved in the maintenance of subclinical disease activity in RA.

Increased synovial galectin-3 induce inflammatory fibroblast activation and osteoclastogenesis in patients with rheumatoid arthritis

OBJECTIVE

Galectin-3 (Gal-3) has been suggested as a proinflammatory mediator in rheumatoid arthritis (RA). We aimed to study clinical and pathogenic aspects of Gal-3 in RA.

METHOD

Plasma samples from healthy controls (n = 48) and patients with newly diagnosed, early RA were assayed for soluble Gal-3. In patients with chronic RA (n = 18), Gal-3 was measured in both plasma and synovial fluid. Synovial fluid mononuclear cells were used to purify fibroblast-like synoviocytes (FLSs) and osteoclasts. Monocultures of FLSs and autologous co-cultures of FLSs and peripheral blood mononuclear cells were established and co-incubated with a Gal-3 inhibitor.

RESULTS

Patients with early and chronic RA had persistently increased plasma levels of Gal-3 compared with controls. However, changes in plasma Gal-3 at the level of individuals were associated with long-term disease activity. In seropositive early RA patients, all patients with decreasing plasma Gal-3 from 0 to 3 months had low disease activity after 2 years (p < 0.05). Gal-3 levels in synovial fluid were markedly elevated. In vitro, co-incubation with a Gal-3 inhibitor (GB1107, 10 µM) led to a significant reduction in both interleukin-1β and tumour necrosis factor-α secretion from FLS monocultures (both p < 0.05) and decreased monocyte-derived osteoclastogenesis compared with controls (both p < 0.05).

CONCLUSIONS

Our findings underscore the role of Gal-3 regarding disease activity and tissue destruction in RA. An initial decrease in plasma Gal-3 levels predicted decreased long-term disease activity. Correspondingly, a Gal-3 inhibitor decreased the activity of inflammatory FLSs and osteoclastogenesis in patients with RA.

Galectin-3 in Microglia-Mediated Neuroinflammation: Implications for Central Nervous System Diseases

Microglial activation is one of the common hallmarks shared by various central nervous system (CNS) diseases. Based on surrounding circumstances, activated microglia play either detrimental or neuroprotective effects. Galectin-3 (Gal-3), a group of β-galactoside-binding proteins, has been cumulatively revealed to be a crucial biomarker for microglial activation after injuries or diseases. In consideration of the important role of Gal-3 in the regulation of microglial activation, it might be a potential target for the treatment of CNS diseases. Recently, Gal-3 expression has been extensively investigated in numerous pathological processes as a mediator of neuroinflammation, as well as in cell proliferation. However, the underlying mechanisms of Gal-3 involved in microgliamediated neuroinflammation in various CNS diseases remain to be further investigated. Moreover, several clinical studies support that the levels of Gal-3 are increased in the serum or cerebrospinal fluid of patients with CNS diseases. Thus, we summarized the roles and underlying mechanisms of Gal-3 in activated microglia, thus providing a better insight into its complexity expression pattern, and contrasting functions in CNS diseases.

Differential impact of biologic therapy on heart function biomarkers in rheumatoid arthritis patients: Observational study on etanercept, adalimumab and tocilizumab

Background Rheumatoid arthritis (RA) represents the most frequent form of inflammatory arthritis affecting approximately 1% of the population worldwide. Introduction of novel therapeutic strategies targeting proinflammatory cytokines (TNF-α and interleukin-6) revolutionized the treatment of RA. This kind of treatment, although effective in a substantial portion of patients, may potentially cause many side effects. Among them cardiovascular safety is one of the main concerns. Objectives In the present study, we investigated what impact treatment with anti-TNF-α and anti-IL-6 agents may have on heart function and levels of heart function biomarkers Methods To measure this, we used cardiac function biomarkers such as NT-pro Brain Natriuretic Peptide, mid regional pro Atrial Natriuretic Peptide, Galectin-3 and Heart-Type Fatty Acid-Binding Protein and compared them to patients treated with methotrexate as well as healthy controls. Results Patients treated with biologics were characterized by low disease activity or were in remission. The disease activity in these groups were significantly lower in comparison to the methotrexate group. All patient recruited to the study were characterized by normal heart function measured with the use of echocardiography (EF>50%). With the exception of MR-proANP between tocilizumab and adalimumab (median: 1.01 vs 0.49 nmol/L, p < 0.05), we failed to observe any significant differences in biomarkers levels between groups treated with biologics. Contrary to this, patients on MTX showed higher NT-proBNP levels compared to adalimumab, and healthy controls (p < 0.05 for both). Striking differences have been shown in regard to H-FABP. The levels of these biomarkers were elevated in all biologics and the methotrexate group as compared to healthy controls. Conclusion As this biomarker reflects potential heart injury we suggest that heart damage proceeds in continuous manner in RA patients despite effective treatment and attainment of remission/low disease activity. This finding however should be verify in larger cohort of RA patients to ascertain if routine assessment of H-FABP may be useful for detection of patients with RA who are at risk of development of heart damage.

Genetic variants in LGALS3 are related to lower galectin-3 serum levels and clinical outcomes in systemic sclerosis patients: A case-control study

INTRODUCTION

Systemic sclerosis (SSc) is a rare complex disease characterized by vascular damage, autoimmunity, and extensive skin and internal organs fibrosis. Galectin-3 (Gal-3) is encoded by gene LGALS3 (Lectin, Galactoside-Binding, Soluble, 3; 14q22.3) and it has been reported to play a central role in self-tolerance, inflammation, and fibrosis.

OBJECTIVE

To investigate associations among LGALS3 single nucleotide polymorphisms (SNPs) and serum levels Gal-3 and SSc susceptibility and their clinical features.

METHODS

A case-control study with 88 patients and 151 matched controls was performed. LGALS3 variants were analyzed by the TaqMan real-time polymerase chain reaction (PCR) system whereas Gal-3 serum levels were measured by sandwich enzyme linked immunosorbent assay (ELISA). Associations among genotypes, clinical features, and Gal-3 levels were performed by univariable and multivariable analysis through statistical packages.

RESULTS

The LGALS3 rs4652 A/C genotype was more frequent in SSc patients than controls according to overdominant model [OR 1.89 (CI 95% 1.01 - 3.52); p = .046]. Also, LGALS3 rs4652 C/C polymorphic genotype was associated with lower patient Gal-3 levels (p = .03) and control group (p = 0.005), as noted by generalized linear model (GLM). The LGALS3 rs1009977 G/T controls showed higher Gal-3 levels than wild-type and polymorphic genotypes (p = .03); however, in SSc patients, no difference was found. None of the LGALS3 SNPs or Gal-3 levels was associated with clinical manifestations in SSc patients. Considering only the SSc group, GLM analysis pointed LGALS3 rs4652 and rs2075601, pulmonary arterial hypertension (PAH), myopathy, and health assessment questionnaire (HAQ) and scleroderma health assessment questionnaire (SHAQ) as important predictors for Gal-3 levels.

CONCLUSION

The LGALS3 rs4652 A/C was more frequent in SSc patients and related to lower Gal-3 levels. These findings were corroborated through a GLM to estimate Gal-3 values. Also, by model equations, Gal-3 levels may be predicted by HAQ, SHAQ, PAH, myopathy, and LGALS3 rs4652 and rs2075601 factors. In these ways, we suggest that galectins may be promising biomarkers to identify susceptibility to SSc as well as to identify HAQ, SHAQ, PAH, and myopathy outcomes.

Loss of α2-6 sialylation promotes the transformation of synovial fibroblasts into a pro-inflammatory phenotype in arthritis

In healthy joints, synovial fibroblasts (SFs) provide the microenvironment required to mediate homeostasis, but these cells adopt a pathological function in rheumatoid arthritis (RA). Carbohydrates (glycans) on cell surfaces are fundamental regulators of the interactions between stromal and immune cells, but little is known about the role of the SF glycome in joint inflammation. Here we study stromal guided pathophysiology by mapping SFs glycosylation pathways. Combining transcriptomic and glycomic analysis, we show that transformation of fibroblasts into pro-inflammatory cells is associated with glycan remodeling, a process that involves TNF-dependent inhibition of the glycosyltransferase ST6Gal1 and α2-6 sialylation. SF sialylation correlates with distinct functional subsets in murine experimental arthritis and remission stages in human RA. We propose that pro-inflammatory cytokines remodel the SF-glycome, converting the synovium into an under-sialylated and highly pro-inflammatory microenvironment. These results highlight the importance of glycosylation in stromal immunology and joint inflammation.

The effect of initial periodontal treatment on gingival crevicular fluid galectin-3 levels in participants with periodontal disease

BACKGROUND

The aim of study was to evaluate galectin-3 levels in gingival crevicular fluid (GCF) from periodontally healthy (H) patients and those with periodontitis (P), gingivitis (G) and the effect of initial periodontal treatment on GCF galectin-3 level.

METHODS

A total of 75 participants, 25 patients with periodontitis, 25 with gingivitis and 25 periodontally healthy subjects were included into the study. Patients with periodontal disease received initial periodontal treatment. GCF galectin-3 level was assessed at baseline and at the 6th-8th weeks after completion of periodontal treatment. GCF galectin-3 level was evaluated by enzyme-linked immunosorbent assay.

RESULTS

GCF galectin-3 level was the lowest in the H group (102.31[63.07] μg/30 s), followed by the G group (241.45[145.89] μg/30 s) and the highest in the P group (338.27[219.37] μg/30 s). These differences were statistically significant between H and the other groups (P < 0.001). After initial periodontal treatment, GCF galectin-3 level significantly decreased in the G and P groups compared to baseline values (P < 0.01).

CONCLUSION

The results of this study suggest that GCF galectin-3 level is a potential biomarker for the evaluation of gingival inflammation and initial periodontal treatment is effective in decreasing GCF galectin-3 level.

Expression and antibacterial analysis of galectin-8 and -9 genes in mandarin fish, Siniperca chuatsi

Galectin-8 and galectin-9 belong to tandem repeat-type galectins, and in the present study, these two genes were cloned in mandarin fish Siniperca chuatsi. The open reading frame (ORF) of the mandarin fish galectin-8 and galectin-9 contains 942, and 1008 bp, encoding 313 and 335 amino acids, respectively. As a conserved feature, an N-terminal carbohydrate recognition domain (CRD), and a C-terminal CRD were observed in each of the two galectins in mandarin fish. In healthy fish, galectin-8 and -9 were constitutively expressed in all organs/tissues examined, and their expression can be induced following the stimulation of LPS and poly(I:C). It is obvious that galectin-8 had a higher increase at mRNA level following the stimulation of poly(I:C). It is further demonstrated that mandarin fish galectin-8 inhibited the growth of Flavobacterium columnare and Streptococcus agalactiae, and in addition to the two species of bacteria, galectin-9 inhibited also the growth of Edwardsiella piscicida, which provides the basis for further understanding their antibacterial role in immune response of mandarin fish.

Effects of Catalpa Alcohol From Rehmannia glutinosa on Calcium-Binding Protein, Interleukin-1β, and Galectin-3 in Synovial Tissues of Rats With Knee Osteoarthritis

Objectives

We aimed to evaluate the effects of catalpa alcohol from Rehmannia glutinosa on the expressions of calcium-binding protein (S100A12), interleukin-1β (IL-1β), and galectin-3 in the synovium of rats with early knee osteoarthritis (KOA).

Methods

Fifty-two adult male Wistar rats aged 3 to 8 weeks were divided into normal control (n = 16), model (n = 12), low-dose (n = 12), and high-dose groups (n = 12). On the 10th day after modeling, 6 rats in normal control group and 6 in the other 3 groups were randomly selected. X-ray and 3-dimensional computed tomography (3D CT) images of the left knee joint were taken under live anesthesia. The joint cavity of sacrificed rats was opened to observe cartilage surface. After 28 consecutive days of administration, the synovial tissue of left knee joint was collected.

Results

The S100A12, IL-1β, and galectin-3 levels in synovial tissue were detected by immunohistochemistry and ELISA. There were articular cartilage defects in left knees. Radiologic examination showed significant joint space narrowing and hyperplasia, and 3D CT joint space value decreased (P &lt; 0.05). The Mankins and OARSI scores of synovial histopathology were significantly different (P &lt; 0.05). The S100A12, IL-1β, and galectin-3 levels in synovial tissue of the model group significantly exceeded those of the normal control group (P &lt; 0.01). Compared with the model group, such levels of low-dose (P &lt; 0.05) and high-dose groups (P &lt; 0.01) were significantly lower.

Conclusions

The S100A12, IL-1β and galectin-3 levels in synovium tissue decreased with rising concentration of catalpa alcohol from R. glutinosa. Therefore, this drug is potentially suitable for inhibiting an inflammatory response to delay the progression of KOA.

A Synthetic Tetramer of Galectin-1 and Galectin-3 Amplifies Pro-apoptotic Signaling by Integrating the Activity of Both Galectins

Galectin-1 (G1) and galectin-3 (G3) are carbohydrate-binding proteins that can signal apoptosis in T cells. We recently reported that a synthetic tetramer with two G1 and two G3 domains ("G1/G3 Zipper") induces Jurkat T cell death more potently than G1. The pro-apoptotic signaling pathway of G1/G3 Zipper was not elucidated, but we hypothesized based on prior work that the G1 domains acted as the signaling units, while the G3 domains served as anchors that increase glycan-binding affinity. To test this, here we studied the involvement of different cell membrane glycoproteins and intracellular mediators in pro-apoptotic signaling via G1/G3 Zipper, G1, and G3. G1/G3 Zipper induced Jurkat T cell death more potently than G1 and G3 alone or in combination. G1/G3 Zipper, G1, and G3 increased caspase-8 activity, yet only G1 and G3 depended on it to induce cell death. G3 increased caspase-3 activity more than G1/G3 Zipper and G1, while all three galectin variants required it to induce cell death. JNK activation had similar roles downstream of G1/G3 Zipper, G1, and G3, whereas ERK had differing roles. CD45 was essential for G1 activity, and was involved in signaling via G1/G3 Zipper and G3. CD7 inhibited G1/G3 Zipper activity at low galectin concentrations but not at high galectin concentrations. In contrast, CD7 was necessary for G1 and G3 signaling at low galectin concentration but antagonistic at high galectin concentrations. Collectively, these observations suggest that G1/G3 Zipper amplifies pro-apoptotic signaling through the integrated activity of both the G1 and G3 domains.

Galectins-1 and -3 in Human Intervertebral Disc Degeneration: Non-Uniform Distribution Profiles and Activation of Disease Markers Involving NF-κB by Galectin-1

Degeneration of the human intervertebral disc (IVD) is assumed to underlie severe clinical symptoms, in particular chronic back pain. Since adhesion/growth-regulatory galectins are linked to arthritis/osteoarthritis pathogenesis by activating a pro-degradative/-inflammatory gene expression signature, we hypothesized a similar functional involvement of galectins in IVD degeneration. Immunohistochemical evidence for the presence of galectins-1 and -3 in IVD is provided comparatively for specimens of spondylochondrosis, spondylolisthesis, and spinal deformity. Immunopositivity was detected in sections of fixed IVD specimens in each cellular compartment with age-, disease-, and galectin-type-related differences. Of note, presence of both galectins correlated with IVD degeneration, whereas correlation with age was seen only for galectin-3. In addition, staining profiles for these two galectins showed different distribution patterns in serial sections, an indication for non-redundant functionalities. In vitro, both galectins bound to IVD cells in a glycan-dependent manner. However, exclusively galectin-1 binding triggered a significant induction of functional disease markers (i.e., IL6, CXCL8, and MMP1/3/13) with involvement of the nuclear factor-kB pathway. This study thus gives direction to further network analyses and functional studies on galectins in IVD degeneration. © 2019 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 37:2204-2216, 2019.

Differences in Inflammation and Bone Resorption between Apical Granulomas, Radicular Cysts, and Dentigerous Cysts

INTRODUCTION

Dental cysts can be of inflammatory (radicular cysts) or noninflammatory (dentigerous cysts) origin. Apical periodontitis is a necrosis of the pulp and infection of the root canal causing the development of apical granulomas or radicular cysts. The immunology of granuloma and cyst formation is important because modern root filling materials are immunologically active and can contribute to the resolution of apical granulomas. In contrast, radicular cysts often require apicectomy. A better understanding of the pathophysiology of inflammation and bone resorption in apical periodontitis could be the basis for developing new root filling materials with superior immunomodulatory properties.

METHODS

Forty-one apical granulomas, 23 radicular cysts, and 23 dentigerous cysts were analyzed in this study. A tissue microarray of the 87 consecutive specimens was created, and human leukocyte antigen-DR isotype (HLA-DR)-, CD83-, receptor activator of nuclear factor kappa B ligand-, macrophage colony-stimulating factor (MCSF)-, galectin-3 (Gal3)-, CD4-, and CD8-positive cells were detected by immunohistochemistry. Tissue microarrays were digitized, and the expression of markers was quantitatively assessed.

RESULTS

HLA-DR, CD83, MCSF, and Gal3 expression was significantly (P < .05) higher in radicular cysts compared with apical granulomas. HLA-DR, CD83, MCSF, receptor activator of nuclear factor kappa B ligand, and Gal3 expression in dentigerous cysts was significantly (P < .05) lower than in both periapical lesions (apical granulomas and radicular cysts). CD4 and CD8 infiltration was not statistically different between apical granulomas and radicular cysts. Dentigerous cysts showed a significantly (P < .05) lower T-cell infiltration than apical periodontitis. The CD4/CD8 ratio was not significantly different between the analyzed groups.

CONCLUSIONS

The development of radicular cysts in apical periodontitis is associated with an increased expression of myeloid inflammatory markers and bone resorption parameters. Antigen-presenting cells and myeloid cells might be more relevant for the pathogenesis of apical periodontitis than T cells. Increased inflammation might promote the formation of radicular cysts and more pronounced bone resorption.

Galectin-3 deficiency protects lipopolysaccharide-induced chondrocytes injury via regulation of TLR4 and PPAR-γ-mediated NF-κB signaling pathway

The aim of the present study was to identify the functional role of galectin-3 (Gal-3) in lipopolysaccharide (LPS)-induced injury in ATDC5 cells and to explore the probable molecular mechanisms. Here, we identified that LPS is sufficient to enhance the expression of Gal-3 in ATDC5 cells. In addition, repression of Gal-3 obviously impeded LPS-stimulated inflammation damage as exemplified by a reduction in the release of inflammatory mediators interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, as well as the production of nitric oxide and prostaglandin E2 (PGE2) concomitant with the downregulation of matrix metalloproteinases (MMP)-13 and MMP-3 expression in ATDC5 cells after LPS administration. Moreover, ablation of Gal-3 dramatically augmented cell ability and attenuated cell apoptosis accompanied by an increase in the expression of antiapoptotic protein Bcl-2 and a decrease in the expression of proapoptotic protein Bax and caspase-3 in ATDC5 cells subjected with LPS. Importantly, we observed that forced expression of TLR4 or blocked PPAR-γ with the antagonist GW9662 effectively abolished Gal-3 inhibition-mediated anti-inflammatory and antiapoptosis effects triggered by LPS. Mechanistically, depletion of Gal-3 prevents the NF-κB signaling pathway. Taken together, these findings indicated that the absence of Gal-3 exerted chondroprotective properties dependent on TLR4 and PPAR-γ-mediated NF-κB signaling, indicating that Gal-3 functions as a protector in the development and progression of osteoarthritis.

Chronic Heart Failure in Rheumatoid Arthritis Patients (Part II): Difficulties of Diagnosis

Rheumatoid arthritis (RA) is characterized by a twofold increase in morbidity and mortality due to chronic heart failure (CHF). At the same time, the prevalence of CHF among RA patients is significantly underestimated. The aim of the review was to analyze the results of the main studies on the features of the clinical presentation of heart failure (HF) in RA patients, the role of visualization techniques and biomarkers in the diagnosis of HF and preclinical dysfunction of the myocardium. HF in patients with RA is characterized by a predominance of HF with a preserved left ventricular ejection fraction (LVEF). The use of clinical diagnostic criteria in RA patients can lead to both over- or underdiagnosis of CHF. Systolic dysfunction estimated by LVEF is rare in RA and does not reflect the real frequency of myocardial dysfunction. Echocardiography (ECHO-CG) with tissue Doppler echocardiography (TDE) and visualization of myocardial deformation, magnetic resonance imaging (MRI) of the heart in RA patients revealed a high frequency of HF with preserved ejection fraction, left ventricular remodeling and hypertrophy, pre-clinical systolic and diastolic dysfunction. Determination of natriuretic peptides is useful for verifying the diagnosis of HF and estimating the prognosis in this cohort, despite the possible decrease in the sensitivity and specificity of these indicators in RA patients. The review discusses the advantages of MRI of the heart, including quantitative T1 and T2 regimens, in the diagnosis of myocarditis, myocardial fibrosis, and myocardial perfusion disorders in RA patients. In order to verify the diagnosis of heart failure and detect pre-clinical myocardial dysfunction in RA patients, the determination of natriuretic peptides concentration should become part of the routine examination, beginning with the debut of the disease, along with the collection of a cardiological history, physical examination, ECHO-CT with TDE, and visualization of myocardial deformation. Evaluation of the quantitative characteristics of tissue according to MRI of the heart could improve the diagnosis of myocardial damage.

Association of galectin-3 with markers of myocardial function, atherosclerosis, and vascular fibrosis in patients with rheumatoid arthritis

BACKGROUND

Galectin-3 has emerged as a promising novel biomarker of cardiovascular fibrosis in patients with cardiovascular diseases.

HYPOTHESIS

We investigated whether galectin-3 correlates with markers of vascular fibrosis, subclinical atherosclerosis, and cardiac function in patients with rheumatoid arthritis (RA), a disease accompanied by high cardiovascular risk.

METHODS

RA and non-RA individuals underwent applanation tonometry, carotid ultrasound, and impedance cardiography, to obtain markers of arterial stiffness, subclinical atherosclerosis, and myocardial function, respectively. Cardiovascular risk was estimated from the Framingham Heart Study. Serum levels of galectin-3 were determined by enzyme-linked immunosorbent assay.

RESULTS

Galectin-3 was elevated in RA patients (n = 85) compared to controls (n = 39), but this difference was no longer significant after adjustment for the presence of cardiovascular comorbidities. In the univariate analysis, galectin-3 significantly correlated with markers of vascular stiffness (including pulse wave velocity, central blood pressure, central and peripheral pulse pressure, and total arterial compliance); atherosclerosis (carotid intima-media thickness); myocardial blood flow (cardiac output, stroke volume) and contractibility (acceleration and velocity index); systemic vascular resistance, and estimated cardiovascular risk. Multivariate analysis models revealed an independent association between galectin-3 and both cardiac output (β = -0.274, P = 0.039), as well as systemic vascular resistance (β = 0.266, P = 0.039).

CONCLUSIONS

In a relatively well-controlled cohort of RA patients with low-grade systemic inflammation and long-standing disease, serum galectin-3 might be useful as a marker of cardiac function and cardiovascular fibrosis.

Galectin-3: One Molecule for an Alphabet of Diseases, from A to Z

Galectin-3 (Gal-3) regulates basic cellular functions such as cell-cell and cell-matrix interactions, growth, proliferation, differentiation, and inflammation. It is not surprising, therefore, that this protein is involved in the pathogenesis of many relevant human diseases, including cancer, fibrosis, chronic inflammation and scarring affecting many different tissues. The papers published in the literature have progressively increased in number during the last decades, testifying the great interest given to this protein by numerous researchers involved in many different clinical contexts. Considering the crucial role exerted by Gal-3 in many different clinical conditions, Gal-3 is emerging as a new diagnostic, prognostic biomarker and as a new promising therapeutic target. The current review aims to extensively examine the studies published so far on the role of Gal-3 in all the clinical conditions and diseases, listed in alphabetical order, where it was analyzed.

Galectin-3 as a novel biomarker for disease diagnosis and a target for therapy (Review)

Galectin-3 is a member of the galectin family, which are β‑galactoside‑binding lectins with ≥1 evolutionary conserved carbohydrate‑recognition domain. It binds proteins in a carbohydrate‑dependent and ‑independent manner. Galectin‑3 is predominantly located in the cytoplasm; however, it shuttles into the nucleus and is secreted onto the cell surface and into biological fluids including serum and urine. It serves important functions in numerous biological activities including cell growth, apoptosis, pre‑mRNA splicing, differentiation, transformation, angiogenesis, inflammation, fibrosis and host defense. Numerous previous studies have indicated that galectin‑3 may be used as a diagnostic or prognostic biomarker for certain types of heart disease, kidney disease and cancer. With emerging evidence to support the function and application of galectin‑3, the current review aims to summarize the latest literature regarding the biomarker characteristics and potential therapeutic application of galectin‑3 in associated diseases.

Role of Galectin-3 in Bone Cell Differentiation, Bone Pathophysiology and Vascular Osteogenesis

Galectin-3 is expressed in various tissues, including the bone, where it is considered a marker of chondrogenic and osteogenic cell lineages. Galectin-3 protein was found to be increased in the differentiated chondrocytes of the metaphyseal plate cartilage, where it favors chondrocyte survival and cartilage matrix mineralization. It was also shown to be highly expressed in differentiating osteoblasts and osteoclasts, in concomitance with expression of osteogenic markers and Runt-related transcription factor 2 and with the appearance of a mature phenotype. Galectin-3 is expressed also by osteocytes, though its function in these cells has not been fully elucidated. The effects of galectin-3 on bone cells were also investigated in galectin-3 null mice, further supporting its role in all stages of bone biology, from development to remodeling. Galectin-3 was also shown to act as a receptor for advanced glycation endproducts, which have been implicated in age-dependent and diabetes-associated bone fragility. Moreover, its regulatory role in inflammatory bone and joint disorders entitles galectin-3 as a possible therapeutic target. Finally, galectin-3 capacity to commit mesenchymal stem cells to the osteoblastic lineage and to favor transdifferentiation of vascular smooth muscle cells into an osteoblast-like phenotype open a new area of interest in bone and vascular pathologies.

Galectin-3 is Persistently Increased in Early Rheumatoid Arthritis (RA) and Associates with Anti-CCP Seropositivity and MRI Bone Lesions, While Early Fibrosis Markers Correlate with Disease Activity

Galectin-3 has been suggested as a pro-inflammatory mediator in animal arthritis and rheumatoid arthritis (RA). We aimed to study the serum level of galectin-3 in patients with newly diagnosed RA and associations with disease profile, Magnetic resonance imaging (MRI) findings and seromarkers of synovial matrix inflammation. One hundred and sixty DMARD naïve patients newly diagnosed with RA were included (CIMESTRA study). Clinical, serological and imaging data were recorded before treatment and at 6 weeks, 3 and 12 months. Galectin-3 and hyaluronan (HYA) were measured by ELISA (R&D and Corgenix, USA), and the N-terminal propeptide of type III collagen (PIIINP) by radioimmunoassay (Orion Diagnostica, Finland). One hundred and nineteen, 87 and 60 blood donors served as controls for galectin-3, HYA and PIIINP, respectively. Baseline galectin-3 was significantly elevated in anti-CCP positive (4.2 μg/l IQR [3.6;6.1]) patients as compared with anti-CCP negatives (4.0 μg/l [2.6;4.9], P = 0.05) and controls (3.8 μg/l [3.0;4.8], P < 0.01). During treatment, galectin-3 remained elevated, but increased transiently with peak values at 6 weeks. Galectin-3 correlated with baseline smoking, anti-CCP, and with MRI erosion score after 1 year of follow-up. HYA and PIIINP were elevated (P < 0.001) irrespective of anti-CCP status and correlated positively with synovitis assessed clinically and by MRI. HYA and PIIINP did not correlate with galectin-3. These observations indicate that HYA and PIIINP mainly reflect expansive synovitis proliferation while galectin-3 is more closely linked to autoimmunity, smoking and joint destructive processes.

Lectin, galactoside-binding, soluble, 3 rs4652 A/C gene variation and the risk for rheumatoid arthritis

Rheumatoid arthritis (RA) is a complex genetic disease. The lectin, galactoside-binding, soluble, 3 (LGALS3) gene, encodes a member of the galectin family of carbohydrate binding proteins, and is one of the best examples of a non-human leukocyte antigen gene associated with a risk for RA in various populations. In the current study, the association between LGALS3 rs4652 gene polymorphism and RA was examined. This case-control study was performed on the 120 patients with RA and 120 healthy subjects. Genomic DNA was extracted from whole blood, and gene polymorphism was tested using a tetra-primer amplification refractory mutation system-polymerase chain reaction. The results demonstrated that LGALS3 rs4652 AC genotype increased the risk of RA (OR=11.622, 95% CI=4.473-28.656; P=0.001) when compared with the AA genotype. However, the CC genotype and the C allele were not associated with RA. These findings indicated an association between LGALS3 rs4652 variation and the risk of RA in a sample of Iranian individuals. Further studies with larger sample sizes and populations of different ethnicities are required to validate our findings.