Insight into the role of IRF7 in skin and connective tissue diseases.

Interferons (IFNs) are signalling proteins primarily involved in initiating innate immune responses against pathogens and promoting the maturation of immune cells. Interferon Regulatory Factor 7 (IRF7) plays a pivotal role in the IFNs signalling pathway. The activation process of IRF7 is incited by exogenous or abnormal nucleic acids, which is followed by the identification via pattern recognition receptors (PRRs) and the ensuing signalling cascades. Upon activation, IRF7 modulates the expression of both IFNs and inflammatory gene regulation. As a multifunctional transcription factor, IRF7 is mainly expressed in immune cells, yet its presence is also detected in keratinocytes, fibroblasts, and various dermal cell types. In these cells, IRF7 is critical for skin immunity, inflammation, and fibrosis. IRF7 dysregulation may lead to autoimmune and inflammatory skin conditions, including systemic scleroderma (SSc), systemic lupus erythematosus (SLE), Atopic dermatitis (AD) and Psoriasis. This comprehensive review aims to extensively elucidate the role of IRF7 and its signalling pathways in immune cells and keratinocytes, highlighting its significance in skin-related and connective tissue diseases.

Regulatory T-cell deficiency leads to features of autoimmune liver disease overlap syndrome in scurfy mice.

Introduction: Scurfy mice have a complete deficiency of functional regulatory T cells (Treg) due to a frameshift mutation in the Foxp3 gene. The impaired immune homeostasis results in a lethal lymphoproliferative disorder affecting multiple organs, including the liver. The autoimmune pathology in scurfy mice is in part accompanied by autoantibodies such as antinuclear antibodies (ANA). ANA are serological hallmarks of several autoimmune disorders including autoimmune liver diseases (AILD). However, the underlying pathogenesis and the role of Treg in AILD remain to be elucidated. The present study therefore aimed to characterize the liver disease in scurfy mice. Methods: Sera from scurfy mice were screened for ANA by indirect immunofluorescence assay (IFA) and tested for a wide range of AILD-associated autoantibodies by enzyme-linked immunosorbent assay, line immunoassay, and addressable laser bead immunoassay. CD4+ T cells of scurfy mice were transferred into T cell-deficient B6/nude mice. Monoclonal autoantibodies from scurfy mice and recipient B6/nude mice were tested for ANA by IFA. Liver tissue of scurfy mice was analyzed by conventional histology. Collagen deposition in scurfy liver was quantified via hepatic hydroxyproline content. Real-time quantitative PCR was used to determine fibrosis-related hepatic gene expression. Hepatic immune cells were differentiated by flow cytometry. Results: All scurfy mice produced ANA. AILD-associated autoantibodies, predominantly antimitochondrial antibodies, were detected at significantly higher levels in scurfy sera. CD4+ T cells from scurfy mice were sufficient to induce anti-dsDNA autoantibodies and ANA with an AILD-related nuclear envelope staining pattern. Liver histology revealed portal inflammation with bile duct damage and proliferation, as in primary biliary cholangitis (PBC), and interface hepatitis with portal-parenchymal necroinflammation, as found in autoimmune hepatitis (AIH). In scurfy liver, TNFα and fibrosis-related transcripts including Col1a1, Timp1, Acta2, Mmp2, and Mmp9 were upregulated. The level of proinflammatory monocytic macrophages (Ly-6Chi) was increased, while M2-type macrophages (CD206+) were downregulated compared to wildtype controls. Despite severe hepatic inflammation, fibrosis did not develop within 25 days, which is close to the lifespan of scurfy mice. Discussion: Our findings suggest that Treg-deficient scurfy mice spontaneously develop clinical, serological, and immunopathological characteristics of AILD with overlapping features of PBC and AIH.

Potential role of type I interferon/IP-10 axis in the pathogenesis of anti-MDA5 antibody-positive dermatomyositis.

OBJECTIVES: Dermatomyositis (DM) patients with anti-melanoma differentiation-associated protein 5 (MDA5) antibodies are known for poor prognosis. This study was designed to identify humoral factors that are readily detectable in the disease and may reflect its activity and pathophysiology. METHODS: We first quantified the serum level expression of 28 cytokines in the serum of patients with collagen vascular diseases using bead-based multiplex immunoassays. We completed these evaluations at hospital admission and followed up with three DM patients with anti-MDA5 antibodies during hospitalisation. We also performed an immunohistochemical analysis of skin samples obtained from two patients. RESULTS: The serum level of interferon gamma-induced protein 10 (IP-10) was significantly higher in DM patients with anti-MDA5 antibodies than in those without the antibody, decreasing drastically upon treatment. Interestingly, this time course paralleled not that of interferon (IFN)-γ, which was originally reported to be the inducer of IP-10, but that of IFN-α2. Immunohistochemical analysis revealed that most of the IP-10-positive cells were macrophages. Furthermore, monocytes stimulated with type I IFN in vitro produced IP-10 in a dose-dependent manner. CONCLUSIONS: IP-10 is a potentially useful disease activity marker of DM with anti-MDA5 antibodies, correlating more with IFN-α2 then IFN-γ. IP-10 released from macrophages might prompt the infiltration of macrophages themselves. Thus, the type I IFN/IP-10 axis may play a pivotal role in the pathogenesis of this intractable disease.

Inherited connective tissue diseases highlight macromolecular network interdependences in skin extracellular matrix: a histomorphometric study.

Mutation of just a single extracellular matrix protein, a receptor or enzyme involved in connective tissue metabolism is sufficient to cause systemic pathologies and failure of tissues that are subjected to strong mechanical stresses. Skin histological and computerized image analyses can provide a good qualitative and quantitative indication of these inherited connective tissue diseases. In this study, skin biopsies from young (10 to 25 years) and middle-aged patients (26 to 50 years) suffering from Ehlers-Danlos syndromes (EDS), Marfan syndrome (MS) or pseudoxanthoma elasticum (PXE) were studied after specific staining of both the collagen and elastic networks. Findings from the histomorphometric analyses conducted on skin sections of the patients with EDS, MS and PXE were compared to skin sections of healthy subjects from the same age groups. Our results show that both the collagen and the elastic networks were affected in all the studied pathological cases, but that the adverse changes to the elastic network in older patients were distinct from the physiological changes observed during aging process for healthy subjects. This degenerative process may be explained by an added phenomenon involving a general connective tissue proteolysis.

Alteration of the m6A methylation landscape in a mouse model of scleroderma.

Aim: To explore the N6-methyladenosine (m6A) methylation of mRNAs and its roles in a mouse model of scleroderma. Materials & methods: To evaluate whether the mouse model of scleroderma could meet the experimental requirements, we examined skin tissue specimens by pathological staining and identified the related indicators by quantitative PCR  (qPCR). m6A-tagged mRNAs were identified via m6A epitranscriptomic microarray, and m6A-RNA-immunoprecipitation qPCR and qPCR were performed to confirm microarray data. Results: There were differences in m6A methylation among 843 mRNAs. Further, there were significant differences among Hras, Saa1, Ccl3, Ccl9 and Il1b in terms of methylation and expression. Conclusion: The m6A methylation spectrum in a mouse model of scleroderma may explain the occurrence of scleroderma.

Lay abstract Scleroderma is an autoimmune disease with an unknown etiology. At present there is no effective treatment, and the prognosis is poor. Although m⁶A methylation is the most common RNA modification and affects cell biological function by influencing mRNA expression levels, the role of m⁶A methylation in scleroderma is unknown. Based on a mouse model of scleroderma, we screened and validated mRNAs related to m⁶A regulation, including Hras, Lama3, Stat3, Tnc, Ccl3, Ccl9, Saa1 and Il1b. While the results are encouraging, they are only preliminary. We plan to explore the altered pattern of m⁶A methylation in skin specimens from patients with scleroderma. This study is important for developing biomarkers for diagnosis and treatment of scleroderma in the future.

Coexpression of Helios in Foxp3+ Regulatory T Cells and Its Role in Human Disease.

Regulatory T cells (Tregs) expressing the Foxp3 transcription factor are indispensable for the maintenance of immune system homeostasis. Tregs may lose Foxp3 expression or be reprogrammed into cells that produce proinflammatory cytokines, for example, Th1-like Tregs, Th2-like Tregs, Th17-like Tregs, and Tfh-like Tregs. Accordingly, selective therapeutic molecules that manipulate Treg lineage stability and/or functional activity might have the potential to improve aberrant immune responses in human disorders. In particular, the transcription factor Helios has emerged as an important marker and modulator of Tregs. Therefore, the current review focuses on recent findings on the expression, function, and mechanisms of Helios, as well as the patterns of Foxp3+ Tregs coexpressing Helios in various human disorders, in order to explore the potential of Helios for the improvement of many immune-related diseases. The studies were selected from PubMed using the library of the Nanjing Medical University in this review. The findings of the included studies indicate that Helios expression stabilizes the phenotype and function of Foxp3+ Tregs in certain inflammatory environments. Further, Tregs coexpressing Helios and Foxp3 were identified as a specific phenotype of stronger suppressor immune cells in both humans and animal models. Importantly, there is ample evidence that Helios-expressing Foxp3+ Tregs are relevant to various human disorders, including connective tissue diseases, infectious diseases, solid organ transplantation-related immunity, and cancer. Thus, Helios+Foxp3+CD4+ Tregs could be a valuable target in human diseases, and their potential should be explored further in the clinical setting.

Cholinergic anti-inflammatory pathway and connective tissue diseases.

Connective tissue diseases (CTDs) consist of an extensive range of heterogeneous medical conditions, which are caused by immune-mediated chronic inflammation and influences the various connective tissues of the body. They include rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, vasculitis, Sjögren's syndrome, Behcet's disease, and many other autoimmune CTDs. To date, several anti-inflammatory approaches have been developed to reduce the severity of inflammation or its subsequent organ manifestations. As a logical mechanism to harnesses the undesired inflammation, some studies investigated the role of the intrinsic cholinergic anti-inflammatory pathway (CAP) in the modulation of chronic inflammation. Many different experimental and clinical models have been developed to evaluate the therapeutic significance of the CAP in CTDs. On the other hand, an issue that is less emphasized in this regard is the presence of autonomic neuropathy in CTDs, which influences the efficiency of CAP in such clinical settings. This condition occurs during CTDs and is a well-known complication of patients suffering from them. The advantages and limitations of CAP in the control of inflammatory responses and its possible therapeutic benefits in the treatment of CTDs are the main subjects of the current study. Therefore, this narrative review article is provided based on the recent findings of the complicated role of CAP in CTDs which were retrieved by searching Science Direct, PubMed, Google Scholar, and Web of Science. It seems that delineating the complex influences of CAP would be of great interest in designing novel surgical or pharmacological therapeutic strategies for CTDs therapy.

Interleukin-35 regulates the balance of Th17 and Treg responses during the pathogenesis of connective tissue diseases.

Interleukin (IL)-35 belongs to the IL-12 cytokine family and is a heterodimer of the p35 and Epstein-Barr virus-induced gene 3 (EBI3) subunits. Functionally, IL-35 can promote the proliferation and activation of regulatory T cells (Tregs) and suppress the function of T helper 17 (Th17) cells and other inflammatory cells to inhibit immune responses. In recent years, an abnormal IL-35 expression causing a Th17/Treg imbalance has been associated with the development and progression of several connective tissue diseases (CTDs), such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), dermatomyositis (DM)/polymyositis (PM), and primary Sjögren's syndrome (pSS). Here, we review the role of IL-35 in regulating the balance of Th17/Treg responses in different types of CTDs and provide new insights into the role of IL-35 in these diseases.

The Roles of Tenascins in Cardiovascular, Inflammatory, and Heritable Connective Tissue Diseases.

Tenascins are a family of multifunctional extracellular matrix (ECM) glycoproteins with time- and tissue specific expression patterns during development, tissue homeostasis, and diseases. There are four family members (tenascin-C, -R, -X, -W) in vertebrates. Among them, tenascin-X (TNX) and tenascin-C (TNC) play important roles in human pathologies. TNX is expressed widely in loose connective tissues. TNX contributes to the stability and maintenance of the collagen network, and its absence causes classical-like Ehlers-Danlos syndrome (clEDS), a heritable connective tissue disorder. In contrast, TNC is specifically and transiently expressed upon pathological conditions such as inflammation, fibrosis, and cancer. There is growing evidence that TNC is involved in inflammatory processes with proinflammatory or anti-inflammatory activity in a context-dependent manner. In this review, we summarize the roles of these two tenascins, TNX and TNC, in cardiovascular and inflammatory diseases and in clEDS, and we discuss the functional consequences of the expression of these tenascins for tissue homeostasis.

[Pathogenetic aspects of magnesium deficiency in connective tissue dysplasia syndrome].

The problem of connective tissue dysplasia is currently becoming particularly relevant because of significant increase of individuals with characteristic abnormalities in the structure of connective tissue. The lack of some micronutrients, arising during ontogenesis in the organism, can determine a high risk of worsening connective tissue homeostasis. Recently, the decisive role of magnesium deficiency in the progression of this disease has been demonstrated. The aim of the study was to substantiate the need for magnesium diet therapy in individuals with connective tissue dysplasia basing on the study of the pathogenetic significance of magnesium deficiency in this pathology. Material and methods. The electronic resources of the portals PubMed-NCBI, MEDLINE, the Scientific Electronic Library eLIBRARY.RU, CyberLeninka and the Google Academy were used. Results and discussion. The analysis of the obtained data made it possible to identify fundamentally new provisions on the main mechanisms of the magnesium influence on the metabolic state of all components of connective tissue. It was proved that magnesium deficiency is a predictor of worsening connective tissue homeostasis, increasing in the number of dysplastic symptoms and their severity. This pathogenetically justifies prescribing a balanced diet to patients with connective tissue dysplasia, including products rich in magnesium, taking into account its recommended daily intake, depending on age of patients. Conclusion. Adequate daily intake of magnesium will increase the mechanical properties and functionality of the connective tissue, and should be recommended for patients with connective tissue dysplasia to prevent the development of complications, maintain the quality of life and improve the prognosis for this disease.

A novel deep intronic COL2A1 mutation in a family with early-onset high myopia/ocular-only Stickler syndrome.

PURPOSE: To identify the genetic defect causing early-onset high myopia (eoHM)/ocular-only Stickler syndrome (ocular-STL) in a large Chinese family. METHODS: Genomic DNA and clinical data from a four-generation family with eoHM/ocular-STL were collected. Whole-exome sequencing was performed on one affected member in initial screening. Linkage scan based on microsatellite markers was carried out initially from candidate loci associated with autosomal dominant eoHM and Stickler syndrome. Sanger sequencing was used to detect potential variants. The pathogenicity of candidate variants was evaluated using mini genes ex vivo. RESULTS: Eight patients and five unaffected members in the family participated in the study, in which the patients had high myopia with other variable ocular phenotypes but without extraocular abnormalities. Whole exome sequencing did not detect any potential pathogenic variant in all genes known to associate with the disease. The eoHM/ocular-STL in the family was mapped to markers around COL2A1 by candidate loci linkage scan, with a maximum lod score of 3.31 for D12S1590 at θ = 0. A novel deep intronic variant, c.86-50C > G in intron 1 of COL2A1, was detected by Sanger sequencing and co-segregated with eoHM/ocular-STL in the family. Ex vivo splicing test using mini genes confirmed that the variant created a new splicing acceptor 49 bp before the canonical splicing site of exon 2, resulted in addition of 49 bp fragment in the transcript (from c.86-49 to c.86-1) and premature termination. CONCLUSIONS: Linkage study, bioinformatics prediction, and ex vivo transcript analysis suggest a novel deep intronic variant adjacent to 5-prime of exon 2 of COL2A1, affecting exon 2 splicing, as a potential cause of ocular-STL in a large family. To our knowledge, this is the first report of an intronic variant around exon 2 as a cause of ocular-STL while a series of variants in the coding region of exon 2, a dispensable alternative-splicing exon for extraocular tissues, in COL2A1 have been reported to cause Stickler syndrome-related ocular phenotype alone.

JAK Inhibitors: Prospects in Connective Tissue Diseases.

The dysregulation of the JAK-STAT pathway is associated with various immune disorders. Four JAK inhibitors have been approved for rheumatoid arthritis (RA), and numerous JAK inhibitors are currently being tested in phase II and III trials for the treatment of various autoimmune inflammatory diseases. In this narrative review, we elucidate the involvement of the JAK-STAT signaling pathway in the pathogenesis of connective tissue diseases (CTDs). We also discuss the efficacy of the first- and second-generation JAK inhibitors (tofacitinib, baricitinib, ruxolitinib, peficitinib, filgotinib, upadacitinib, solcitinib, itacitinib, decernotinib, R333, and pf-06651600) for CTDs including RA, systemic lupus erythematosus, dermatomyositis, systemic sclerosis, Sjögren's syndrome, and vasculitis, based on laboratory and clinical research findings. JAK inhibitors have great potential for the treatment of various CTDs by reducing multiple cytokine production and suppressing inflammation, with the advantages of rapid onset in an oral formulation and decreased corticosteroid dependence and the associated adverse events, especially in refractory cases. We also highlight the safety of novel JAK inhibitors, which can cause opportunistic infections, especially viral infections. Being a very recent therapeutic option, information regarding the safety of JAK inhibitors during pregnancy and for pediatric use is limited. However, it is recommended that JAK inhibitors should be avoided in pregnant and breastfeeding women. More clinical data, especially on highly selective inhibitors, are required to judge the efficacy and safety of JAK inhibition in CTDs.

The role of IL-37 in skin and connective tissue diseases.

IL-37 was discovered as an anti-inflammatory and immunosuppressive cytokine of the IL-1 family. Significant advancements in the understanding of signaling pathways associated with IL-37 have been made in recent years. IL-37 binds to IL-18R and recruits IL-1R8 to form the IL-37/IL-1R8/IL-18Rα complex. Capase-1 plays a key role in the nuclear transduction of IL-37 signal, processing precursor IL-37 into the mature isoform, and interacting with Smad3. IL-37 exerts its role by activating anti-inflammation pathways including AMPK, PTEN, Mer, STAT3 and p62, and promoting tolerogenic dendritic cells and Tregs. In addition, IL-37 inhibits pro-inflammatory cytokines such as IL-1, IL-6, IL-8, IL-17, IL-23, TNF-α, and IFN-γ, and suppresses Fyn, MAPK, TAK1, NFκB, and mTOR signaling. The final effects of IL-37 depend on the interaction among IL-18R, IL-1R8, IL-37 and IL-18BP. Previous studies have deciphered the role of IL-37 in the development and pathogenesis of autoimmune diseases, chronic infections and cancer. In this review, we discuss the role of IL-37 in psoriasis, atopic dermatitis, Behcet's diseases, systemic lupus erythematosus, and other skin and connective tissue diseases.

Unique molecular networks: Formation and role of elastin cross-links.

Elastic fibers are essential assemblies of vertebrates and confer elasticity and resilience to various organs including blood vessels, lungs, skin, and ligaments. Mature fibers, which comprise a dense and insoluble elastin core and a microfibrillar mantle, are extremely resistant toward intrinsic and extrinsic influences and maintain elastic function over the human lifespan in healthy conditions. The oxidative deamination of peptidyl lysine to peptidyl allysine in elastin's precursor tropoelastin is a crucial posttranslational step in their formation. The modification is catalyzed by members of the family of lysyl oxidases and the starting point for subsequent manifold condensation reactions that eventually lead to the highly cross-linked elastomer. This review summarizes the current understanding of the formation of cross-links within and between the monomer molecules, the molecular sites, and cross-link types involved and the pathological consequences of abnormalities in the cross-linking process.

Proline-dependent regulation of collagen metabolism.

This review is focused on recent data on the role of proline (Pro) in collagen biosynthesis and cellular metabolism. It seems obvious that one of the main substrates for collagen biosynthesis Pro is required to form collagen molecule. The question raised in this review is whether the Pro for collagen biosynthesis is synthesized "de novo", comes directly from degraded proteins or it is converted from other amino acids. Recent data provided evidence that extracellular Pro (added to culture medium) had significant, but relatively little impact on collagen biosynthesis in fibroblasts (the main collagen synthesized cells) cultured in the presence of glutamine (Gln). However, extracellular Pro drastically increased collagen biosynthesis in the cells cultured in Gln-free medium. It suggests that Pro availability determines the rate of collagen biosynthesis and demand for Pro in fibroblasts is predominantly met by conversion from Gln. The potential mechanism of this process as well as possible implication of this knowledge in pharmacotherapy of connective tissue diseases is discussed in this review.

Shared and distinct mechanisms of fibrosis.

Fibrosis is defined as an excessive deposition of connective tissue components and can affect virtually every organ system, including the skin, lungs, liver and kidney. Fibrotic tissue remodelling often leads to organ malfunction and is commonly associated with high morbidity and mortality. The medical need for effective antifibrotic therapies is thus very high. However, the extraordinarily high costs of drug development and the rare incidence of many fibrotic disorders hinder the development of targeted therapies for individual fibrotic diseases. A potential strategy to overcome this challenge is to target common mechanisms and core pathways that are of central pathophysiological relevance across different fibrotic diseases. The factors influencing susceptibility to and initiation of these diseases are often distinct, with disease-specific and organ-specific risk factors, triggers and sites of first injury. Fibrotic remodelling programmes with shared fibrotic signalling responses such as transforming growth factor-ß (TGFß), platelet-derived growth factor (PDGF), WNT and hedgehog signalling drive disease progression in later stages of fibrotic diseases. The convergence towards shared responses has consequences for drug development as it might enable the development of general antifibrotic compounds that are effective across different disease entities and organs. Technological advances, including new models, single-cell technologies and gene editing, could provide new insights into the pathogenesis of fibrotic diseases and the development of drugs for their treatment.

[Expression and clinical significance of CCL18 in bronchoalveolar lavage fluid of connective tissue disease-associated interstitial lung disease].

Objective: To explore the expression and clinical significance of chemokine ligand 18 (CCL18) in Bronchoalveolar Lavage Fluid (BALF) of patients with connective tissue disease-associated interstitial lung disease (CTD-ILD). Methods: From January 2016 to June 2017, BALF of patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD group), patients with dermatomyositis-associated interstitial lung disease (DM-ILD group), and patients with primary Sjögren syndrome-associated interstitial lung disease (pSS-ILD group) of Peking University People's Hospital were collected. According to the prognosis of each group of patients during hospitalization, they were divided into the discharged and the died. Besides, 30 patients without ILD served as a control group. Levels of CCL18 in BALF of all patients were tested by enzyme linked immunosorbent assay (ELISA). Cells in BALF of RA-ILD group, DM-ILD group and pSS-ILD group were collected and analyzed by absolute different cell counts. Results of high-resolution CT (HRCT) of these three groups were scored. In addition, the area under the curve (AUC) of CCL18 in predicting mortality during hospitalization was calculated. Results: A total of 38 patients with RA-ILD, 54 patients with DM-ILD, and 35 patients with pSS-ILD were enrolled. Levels of CCL18 of those discharged patients of RA-ILD, DM-ILD, and pSS-ILD groups were 8.27(3.62, 14.36), 11.04 (5.86, 17.38), 5.25(2.68, 8.21) µg/L, respectively, which were all significantly higher than that of the control group [2.54(1.26, 3.66) µg/L, all P<0.05]. Furthermore, levels of CCL18 of those deceased patients of RA-ILD and DM-ILD groups were 18.28 (13.82, 22.39), 18.81 (16.29, 22.90) µg/L, which were significantly higher than that of the discharged patients of same group (all P<0.05). Levels of CCL18 were positively correlated with lymphocyte percentage in BALF of RA-ILD, DM-ILD and pSS-ILD groups (r=0.4356, 0.4029, 0.3939, respectively, all P<0.05). Besides, levels of CCL18 were significantly correlated with HRCT scores of RA-ILD and DM-ILD groups (r=0.4242, 0.3319, respectively, both P<0.05). Areas under the curve (AUCs) of CCL18 to predict mortality during hospitalization of RA-ILD and DM-ILD groups were 0.860, 0.851, respectively. Conclusions: Levels of CCL18 are elevated in BALF of CTD-ILD patients, and may be correlated with the severity and prognosis during hospitalization. CCL18 might be served as an indicator of the severity and prognosis of CTD-ILD.

Breast milk concentration of hydroxychloroquine in Chinese lactating women with connective tissue diseases.

PURPOSE: Considering the very limited while varying information about the excretion of hydroxychloroquine (HCQ) into human milk, we sought to determine the breast milk concentrations of HCQ in Chinese lactating patients with connective tissue diseases to assess the safety of HCQ in infants of this population. METHODS: Breastfeeding women who had been on HCQ for at least 1 year were recruited. Milk samples were collected at five time points over 12 h. Breast milk HCQ levels were measured by a validated high-performance liquid chromatography (HPLC) assay. According to the general daily milk consumption of 0.15 L/kg for an infant, the dose of HCQ received by the infants via breastfeeding was calculated. RESULTS: Thirty-three patients completed the study who received HCQ treatment with the following regimens: 0.1 g bid (n = 3), 0.2 g qd (n = 8), 0.2 g bid (n = 21), and 0.2 g qod (n = 1). The mean breast milk HCQ levels (µg/mL) over the 12-h sampling period for each dosage regimen group were 0.4, 0.7, 1.4, and 0.4, respectively. The dose of HCQ (mg) received by the infants via breastfeeding would be 0.4, 0.4, 0.9, and 0.2, which were 0.26%, 0.26%, 0.29%, and 0.26% of the daily maternal doses, respectively. The infant's weight-adjusted relative dose (mg/kg) was 0.1, 0.1, 0.2, and 0.1, respectively, equivalent to 1.9%, 3.0%, 3.0%, and 3.2% of the maternal dose per kilogram body weight, respectively. CONCLUSION: Our study found that HCQ has very low concentrations in breast milk. It is probably safe for the patients to give breastfeeding during HCQ therapy period.

Bone and connective tissue disorders caused by defects in glycosaminoglycan biosynthesis: a panoramic view.

Glycosaminoglycans (GAGs) are a heterogeneous family of linear polysaccharides that constitute the carbohydrate moiety covalently attached to the protein core of proteoglycans, macromolecules present on the cell surface and in the extracellular matrix. Several genetic disorders of bone and connective tissue are caused by mutations in genes encoding for glycosyltransferases, sulfotransferases and transporters that are responsible for the synthesis of sulfated GAGs. Phenotypically, these disorders all reflect alterations in crucial biological functions of GAGs in the development, growth and homoeostasis of cartilage and bone. To date, up to 27 different skeletal phenotypes have been linked to mutations in 23 genes encoding for proteins involved in GAG biosynthesis. This review focuses on recent genetic, molecular and biochemical studies of bone and connective tissue disorders caused by GAG synthesis defects. These insights and future research in the field will provide a deeper understanding of the molecular pathogenesis of these disorders and will pave the way for developing common therapeutic strategies that might be targeted to a range of individual phenotypes.

Mechanism of action of celastrol against rheumatoid arthritis: A network pharmacology analysis.

Network pharmacology uses bioinformatics to broaden our understanding of drug actions and thereby to advance drug discovery. Here we apply network pharmacology to generate testable hypotheses about the multi-target mechanism of celastrol against rheumatoid arthritis. We reconstructed drug-target pathways and networks to predict the likely protein targets of celastrol and the main interactions between those targets and the drug. Then we validated our predictions of four candidate targets (IKK-ß, JNK, COX-2, MEK1) by performing docking studies with celastrol. The results suggest that celastrol acts against rheumatoid arthritis by regulating the function of several signaling proteins, including MMP-9, COX-2, c-Myc, TGF-ß, c-JUN, JAK-1, JAK-3, IKK-ß, SYK, MMP-3, JNK and MEK1, which regulate the functions of Th1 and Th2 cells, macrophages, fibroblasts and endothelial cells in rheumatoid arthritis. Celastrol is predicted to affect networks involved mainly in cancer, connective tissue disorders, organismal injury and abnormalities, tissue development, cell death and survival. This network pharmacology strategy may be useful for discovery of multi-target drugs against complex diseases.