Diverse pro-inflammatory ability of mutated spike protein derived from variant strains of SARS-CoV-2.

The severity of COVID-19 has been reported to differ among SARS-CoV-2 mutant variants. The overactivation of macrophages is involved in severe COVID-19, yet the effects of SARS-CoV-2 mutations on macrophages remain poorly understood. To clarify the effects, we examined whether mutations of spike proteins (S-proteins) affect macrophage activation. CD14+ monocyte-derived macrophages were stimulated with the recombinant S-protein of the wild-type, Delta, and Omicron strains or live viral particles of individual strains. Regarding IL-6 and TNF-α, Delta or Omicron S-protein had stronger or weaker pro­inflammatory ability, respectively, than the wild-type. Similar trends were observed between S-proteins and viral particles. S-protein mutations could be related to the diversity in macrophage activation and severity rates in COVID-19 caused by various SARS-CoV-2 strains.

Effectiveness and safety of treat-to-target strategy for methotrexate-naïve rheumatoid arthritis patients >75 years of age.

Objectives: To identify differences in effectiveness and safety of a treat-to-target (T2T) strategy comparing late-onset MTX-naïve RA patients (LORA) ≥75 or <75 years of age. Methods: Treatment was adjusted to target low disease activity with conventional synthetic DMARDs followed by biologic DMARDs (bDMARDs) in LORA ≥75 years (n = 98, mean age 80.0 years) and LORA <75 years (n = 99) with moderate-high disease activity. Achievement of Simplified Disease Activity Index (SDAI) remission at week 156 by non-responder imputation analysis was evaluated as a primary outcome. Results: LORA ≥75 years had more comorbidities than LORA <75 years, but SDAI and ACPA positivity were similar at baseline. Of the LORA ≥75 years, 70.4% started MTX and 34.1% and 37.1% received a bDMARD at week 52 and 156, respectively (very similar to the LORA <75 years). Glucocorticoid use was more frequent in the LORA ≥75 years than in the LORA <75 years. Comorbidities/adverse events more frequently contributed to the reasons for non-adherence to T2T in the LORA ≥75 than in the LORA <75. At week 156, 32.7% of the LORA ≥75 and 66.7% of the LORA <75 achieved SDAI remission (P < 0.001). The cumulative incidence of serious adverse events (SAEs) over 156 weeks was 42.8% in the LORA ≥75 and 22.1% in the LORA <75. Multivariable analysis indicated an increased risk of SDAI non-remission at week 156 in the LORA ≥75 [odds ratio 2.82 (95% CI 1.29. 6.14)] after adjusting for comorbidities at baseline, non-adherence to T2T and SAEs. Conclusions: It was more difficult to achieve remission in the LORA ≥75 patients than in the LORA <75 patients due to both poor treatment response and safety issues.

Anti-Inflammatory Effects of a Novel Nuclear Factor-κB Inhibitory Derivative Derived from Pyrazolo[3,4-d]Pyrimidine in Three Inflammation Models.

Nuclear factor-κB (NF-κB) plays a central role in inflammatory responses, and its physiologic functions are essential for cell survival and proliferation. Currently, drugs targeting NF-κB inhibition have not yet been applied in clinical practice. We investigated the physiologic effect of a novel NF-κB inhibitory compound, 1H-pyrazolo[3,4-d]pyrimidin-4-amine derivative (INH #1), on three inflammatory animal models. The pharmacokinetics were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. Acute hepatitis was induced by administrating lipopolysaccharide (LPS) and D-(+)-galactosamine hydrochloride followed by the analysis of survival time and inflammatory mediators. Collagen-induced arthritis (CIA) was induced by immunization with type II collagen (CII), and serum-transfer arthritis (STA) was caused by injecting K/BxN mice serum. Clinical and histologic scores were evaluated in both arthritis models. Immune cell subset analysis, CII-induced interferon-gamma (IFN-γ) production and proliferation, and measurement of anti-CII IgG antibodies were performed in the CIA model. In the acute hepatitis model, INH #1 suppressed tumor necrosis factor-α (TNF-α) production and prevented early death in a dose-dependent manner. INH #1 significantly attenuated arthritis scores and joint inflammation in both arthritis models. Additionally, in the CIA model, dendritic cells (DCs) in the regional lymph nodes were decreased in the treated mice and antigen-induced IFN-γ production and cell proliferation in splenocytes were inhibited, whereas the titers of anti-CII IgG antibodies were comparable regardless of the treatment. Here we revealed that INH #1 exerted anti-inflammatory effects in vivo via inhibition of inflammatory mediators and suppression of cellular immune responses. This compound could be a novel candidate for inhibition of NF-κB in certain inflammatory diseases. SIGNIFICANCE STATEMENT: A novel nuclear factor-κB (NF-κB) inhibitory compound, 1H-pyrazolo[3,4-d]pyrimidin-4-amine derivative (INH #1), which retains physiologically essential NF-κB bioactivity, suppressed inflammation in three different mouse models: the acute hepatitis model, the collagen-induced arthritis model, and the K/BxN serum-transfer arthritis model. These results suggest that this compound could be a novel and potent anti-inflammatory agent.

Variations in subtle cystic tumors of the atrioventricular node: Five autopsy cases.

Cystic tumor of the atrioventricular node (CTAVN) is the most common primary cardiac tumor cause of sudden death but is rarely found during forensic autopsy. We present five autopsy cases of sudden death from undiagnosed CTAVN. The tumors varied in their histological appearance, which may be related to their variation in clinical presentation. Some of the cases had been diagnosed with epilepsy before death; it seems that syncopal attacks caused by CTAVN may be misdiagnosed as epilepsy. When performing forensic autopsy, CTAVN should be considered in the differential diagnosis of sudden death. Careful examination of the cardiac conduction system is important in every sudden death case regardless of age.

Thrombosis and antiphospholipid antibodies in Japanese COVID-19: based on propensity score matching.

Background: Thrombosis is a unique complication of coronavirus disease 2019 (COVID-19). Although antiphospholipid antibodies (aPL) are detected in COVID-19 patients, their clinical significance remains elusive. We evaluated the prevalence of aPL and serum concentrations of beta-2 glycoprotein I (ß2GPI), a major self-antigen for aPL, in Japanese COVID-19 patients with and without thrombosis. Methods: This retrospective single-center nested case-control study included 594 hospitalized patients with COVID-19 between January 2020 and August 2021. Thrombotic complications were collected from medical records. Propensity score-matching method (PSM) (1:2 matching including age, sex, severity on admission, and prior history of thrombosis) was performed to compare the prevalence and titer of aPL (anti-cardiolipin (aCL) IgG/IgM, anti-ß2GPI IgG/IgM/IgA, and anti-phosphatidylserine/prothrombin antibody (aPS/PT) IgG/IgM) and serum ß2GPI concentration. In addition, PSM (1:1 matching including age and sex) was performed to compare the serum ß2GPI concentration between COVID-19 patients and healthy donors. Results: Among the patients, 31 patients with thrombosis and 62 patients without were compared. The prevalence of any aPLs was indifferent regardless of the thrombosis (41.9% in those with thrombosis vs. 38.7% in those without, p =0.82). The positive rates of individual aPL were as follows: anti-CL IgG (9.7% vs. 1.6%, p =0.11)/IgM (0% vs. 3.2%, p =0.55), anti-ß2GP1 IgG (22.6% vs. 9.7%, p =0.12)/IgA (9.7% vs. 9.7%, p =1.0)/IgM (0% vs. 0%, p =1.0), and anti-PS/PT IgG (0% vs. 1.6%, p =1.0)/IgM (12.9% vs. 21.0%, p =0.41), respectively. The aPL titers were also similar regardless of thrombosis. The levels of ß2GPI in COVID-19 patients were lower than those in the healthy donors. Conclusion: Although aPLs were frequently detected in Japanese COVID-19 patients, their prevalence and titer were irrelevant to thrombotic complications. While COVID-19 patients have lower levels of serum ß2GPI than healthy blood donors, ß2GPI levels were indifferent regardless of thrombosis. Although most of the titers were below cut-offs, positive correlations were observed among aPLs, suggesting that the immune reactions against aPL antigens were induced by COVID-19. We should focus on the long-term thromboembolic risk and the development of APS in the aPL-positive patients with high titer or multiple aPLs.

Expression of the readthrough transcript CiDRE in alveolar macrophages boosts SARS-CoV-2 susceptibility and promotes COVID-19 severity.

Lung infection during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via the angiotensin-I-converting enzyme 2 (ACE2) receptor induces a cytokine storm. However, the precise mechanisms involved in severe COVID-19 pneumonia are unknown. Here, we showed that interleukin-10 (IL-10) induced the expression of ACE2 in normal alveolar macrophages, causing them to become vectors for SARS-CoV-2. The inhibition of this system in hamster models attenuated SARS-CoV-2 pathogenicity. Genome-wide association and quantitative trait locus analyses identified a IFNAR2-IL10RB readthrough transcript, COVID-19 infectivity-enhancing dual receptor (CiDRE), which was highly expressed in patients harboring COVID-19 risk variants at the IFNAR2 locus. We showed that CiDRE exerted synergistic effects via the IL-10-ACE2 axis in alveolar macrophages and functioned as a decoy receptor for type I interferons. Collectively, our data show that high IL-10 and CiDRE expression are potential risk factors for severe COVID-19. Thus, IL-10R and CiDRE inhibitors might be useful COVID-19 therapies.

Leucine-rich alpha-2 glycoprotein as a potential biomarker for large vessel vasculitides.

Objectives: Serum levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) have been used as useful biomarkers for reflecting the activity of large vessel vasculitides (LVV). However, a novel biomarker that could have a complementary role to these markers is still required. In this retrospective observational study, we investigated whether leucine-rich α-2 glycoprotein (LRG), a known biomarker in several inflammatory diseases, could be a novel biomarker for LVVs. Methods: 49 eligible patients with Takayasu arteritis (TAK) or giant cell arteritis (GCA) whose serum was preserved in our laboratory were enrolled. The concentrations of LRG were measured with an enzyme-linked immunosorbent assay. The clinical course was reviewed retrospectively from their medical records. The disease activity was determined according to the current consensus definition. Results: The serum LRG levels were higher in patients with active disease than those in remission, and decreased after the treatments. While LRG levels were positively correlated with both CRP and erythrocyte sedimentation rate, LRG exhibited inferior performance as an indicator of disease activity compared to CRP and ESR. Of 35 CRP-negative patients, 11 had positive LRG. Among the 11 patients, two had active disease. Conclusion: This preliminary study indicated that LRG could be a novel biomarker for LVV. Further large studies should be required to promise the significance of LRG in LVV.

Apple-shaped obesity: A risky soil for cytokine-accelerated severity in COVID-19.

Obesity has been recognized as one of the most significant risk factors for the deterioration and mortality associated with COVID-19, but the significance of obesity itself differs among ethnicity. Multifactored analysis of our single institute-based retrospective cohort revealed that high visceral adipose tissue (VAT) burden, but not other obesity-associated markers, was related to accelerated inflammatory responses and the mortality of Japanese COVID-19 patients. To elucidate the mechanisms how VAT-dominant obesity induces severe inflammation after severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection, we infected two different strains of obese mice, C57BL/6JHamSlc-ob/ob (ob/ob), C57BLKS/J-db/db (db/db), genetically impaired in the leptin ligand and receptor, respectively, and control C57BL/6 mice with mouse-adapted SARS-CoV-2. Here, we revealed that VAT-dominant ob/ob mice were extremely more vulnerable to SARS-CoV-2 due to excessive inflammatory responses when compared to SAT-dominant db/db mice. In fact, SARS-CoV-2 genome and proteins were more abundant in the lungs of ob/ob mice, engulfed in macrophages, resulting in increased cytokine production including interleukin (IL)-6. Both an anti-IL-6 receptor antibody treatment and the prevention of obesity by leptin replenishment improved the survival of SARS-CoV-2-infected ob/ob mice by reducing the viral protein burden and excessive immune responses. Our results have proposed unique insights and clues on how obesity increases the risk of cytokine storm and death in patients with COVID-19. Moreover, earlier administration of antiinflammatory therapeutics including anti-IL-6R antibody to VAT-dominant patients might improve clinical outcome and stratification of the treatment for COVID-19, at least in Japanese patients.

Hemorrhagic gastric ulcer in a patient with Behcet's disease successfully treated with infliximab.

Behcet's disease (BD) is a multisystem immune-mediated inflammatory disorder that occasionally involves the gastrointestinal tract. Reports on gastrointestinal involvement of BD are relatively rare, of which gastroduodenal involvement is particularly rare. Endoscopic features of gastroduodenal lesions are unknown, and treatment strategies have not been established. In this report, we present the case of a 72-year-old female with gastrointestinal BD who presented with extensive gastroduodenal ulcers and hematemesis that were resistant to colchicine and corticosteroid treatment, which were subsequently successfully treated with infliximab. We also review the current literature on the gastroduodenal involvement of BD. Although rare, the case highlights the importance of being aware of upper gastrointestinal manifestations of BD, as well as demonstrating the potential of infliximab to treat corticosteroid-resistant cases.

Mass-like Lesions Causing Compression of Large Vessels in Granulomatosis with Polyangiitis.

A 69-year-old woman with a history of otitis media with anti-neutrophil cytoplasmic antibody-associated vasculitis who had been receiving corticosteroid monotherapy presented with shortness of breath. The otitis media had been alleviated, but she had saddle nose. Chest enhanced computed tomography showed stenoses of the bronchi and large vessels surrounded by mass-like lesions in the mediastinum. These manifestations indicated an active state of granulomatosis with polyangiitis (GPA). After she was started on high-dose corticosteroids and intravenous cyclophosphamide, the mass-like lesions disappeared with improvements of the stenoses. Ameliorating mass-like lesions resulting from GPA requires therapeutic intervention using corticosteroids and immunosuppressants.

Factors associated with impaired physical function in elderly rheumatoid arthritis patients who had achieved low disease activity.

OBJECTIVE: We aimed to investigate factors associated with impaired physical function (defined as HAQ Disability Index [HAQ-DI] >0.5) of old-old (aged 75-84) patients with rheumatoid arthritis (RA). METHODS: Data from 15,185 RA patients in the National Database of Rheumatic Disease in Japan were extracted from 2017 to 2018. We enrolled 3,708 patients aged 55-84 in simplified disease activity index (SDAI) ≤11 and Steinbrocker stage I/II. Factors associated with HAQ-DI >0.5 were analyzed by multivariable logistic regression. RESULTS: About half of the old-old patients received methotrexate, which was lower than middle-aged (55-64) and young-old patients (65-74). The proportion of glucocorticoids in the old-old patients was highest among the three groups, and biological disease-modifying anti-rheumatic drugs were similarly used. The prevalence of HAQ-DI >0.5 was significantly higher in old-old patients with low disease activity than in those with remission. The same was true in the middle-aged and young-old patients. Multivariable analysis showed age, higher SDAI, glucocorticoid use, and methotrexate non-use were significantly associated with HAQ-DI >0.5 in the old-old patients. CONCLUSIONS: SDAI remission was an ideal goal for old-old patients in terms of physical function. Glucocorticoids and a low proportion of methotrexate use may influence the physical function of old-old patients.

Associated factors with poor treatment response to initial glucocorticoid therapy in patients with adult-onset Still's disease.

BACKGROUND: High-dose glucocorticoids (GC) are first-line treatment for adult-onset Still's disease (AOSD); however, some of the patients remain refractory to initial GC therapy, or rapidly relapse. The aim of this study was to identify prognostic factors for poor treatment response to initial GC therapy for AOSD. METHODS: Data on newly diagnosed AOSD patients were extracted from our database (n=71, mean age 51.6 years). The primary outcome was a poor treatment outcome at 4 weeks, which was defined as failure to achieve remission or relapse after achieving remission within 4 weeks, followed by administration of two or more rounds of GC pulse therapy or of any other immunosuppressive drugs. RESULTS: The initial mean dose ± standard deviation of prednisolone was 0.82 ± 0.23 mg/kg/day, and 34 (47.3%) patients received GC pulse therapy at week 0. Twenty-nine of 71 patients exhibited a poor treatment outcome at 4 weeks (40.8%). The second round of GC pulse therapy or immunosuppressive drugs was added in 17 or 24 of the 29 patients, respectively. These patients had higher baseline white blood cell (WBC) counts, serum ferritin levels, systemic feature score based on clinical symptoms (modified systemic feature score, mSFS), more hemophagocytic syndrome (HPS) over the 4 weeks, and the higher severity score based on modified Pouchot score or severity index of the Japanese Ministry of Health, Labour and Welfare, than the remaining 42 patients. Multivariable logistic regression model identified baseline WBC count as a prognostic factor for poor outcome (odds ratio per 1000/µl increment: 1.12, 95% CI 1.04-1.29), while thrombocytopenia, hyperferritinemia, and mSFS at baseline did not achieve statistical significance. Receiver-operating characteristic curve analysis showed that the optimal cut-off for WBC count was 13,050/µl. The Kaplan-Meier method showed the cumulative rate of poor treatment outcome to be 60.0% in patients with WBC ≥13,050/µl and 23.5% in those with WBC <13,050/µl. CONCLUSIONS: A higher WBC count but not thrombocytopenia, hyperferritinemia, and mSFS at baseline was a significant prognostic factor for poor treatment outcome at week 4 in this retrospective cohort of AOSD patients. Our findings provide important information for determining the initial treatment strategy of newly-diagnosed AOSD.

CD34+THY1+ synovial fibroblast subset in arthritic joints has high osteoblastic and chondrogenic potentials in vitro.

OBJECTIVE: Synovial fibroblasts (SFs) in rheumatoid arthritis (RA) and osteoarthritis (OA) play biphasic roles in joint destruction and regeneration of bone/cartilage as mesenchymal stem cells (MSCs). Although MSCs contribute to joint homeostasis, such function is impaired in arthritic joints. We have identified functionally distinct three SF subsets characterized by the expression of CD34 and THY1 as follows: CD34+THY1+, CD34-THY1-, and CD34-THY1+. The objective of this study was to clarify the differentiation potentials as MSCs in each SF subset since both molecules would be associated with the MSC function. METHODS: SF subsets were isolated from synovial tissues of 70 patients (RA: 18, OA: 52). Expressions of surface markers associated with MSCs (THY1, CD34, CD73, CD271, CD54, CD44, and CD29) were evaluated in fleshly isolated SF subsets by flow cytometry. The differentiation potentials of osteogenesis, chondrogenesis, and adipogenesis were evaluated with histological staining and a quantitative polymerase chain reaction of differentiation marker genes. Small interfering RNA was examined to deplete THY1 in SFs. RESULTS: The expression levels of THY1+, CD73+, and CD271+ were highest and those of CD54+ and CD29+ were lowest in CD34+THY1+ among three subsets. Comparing three subsets, the calcified area, alkaline phosphatase (ALP)-stained area, and cartilage matrix subset were the largest in the CD34+THY1+ subset. Consistently, the expressions of differentiation markers of the osteoblasts (RUNX2, ALPL, and OCN) or chondrocytes (ACAN) were the highest in the CD34+THY1+ subset, indicating that the CD34+THY1+ subset possessed the highest osteogenic and chondrogenic potential among three subsets, while the differentiation potentials to adipocytes were comparable among the subsets regarding lipid droplet formations and the expression of LPL and PPARγ. The knockdown of THY1 in bulk SFs resulted in impaired osteoblast differentiation indicating some functional aspects in this stem-cell marker. CONCLUSION: The CD34+THY1+ SF subset has high osteogenic and chondrogenic potentials. The preferential enhancement of MSC functions in the CD34+THY1+ subset may provide a new treatment strategy for regenerating damaged bone/cartilage in arthritic joints.

Small Molecule Calcium Channel Activator Potentiates Adjuvant Activity.

There remains an unmet need for reliable fully synthetic adjuvants that increase lasting protective immune responses from vaccines. We previously reported a high-throughput screening for small molecules that extended nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) activation after a Toll-like receptor 4 (TLR4) ligand, lipopolysaccharide (LPS), stimulation using a human myeloid reporter cell line. We identified compounds with a conserved aminothiazole scaffold including 2D216 [N-(4-(2,5-dimethylphenyl)thiazol-2-yl)-4-(piperidin-1-ylsulfonyl)benzamide], which increased murine antigen-specific antibody responses when used as a co-adjuvant with LPS. Here, we examined the mechanism of action in human cells. Although 2D216 activated the major mitogen-activated protein kinases, it did not interact with common kinases and phosphatases and did not stimulate many of the pattern recognition receptors (PRRs). Instead, the mechanism of action was linked to intracellular Ca2+ elevation via Ca2+ channel(s) at the plasma membrane and nuclear translocation of the nuclear factor of activated T-cells (NFAT) as supported by RNA-seq data, analysis by reporter cells, Ca2+ flux assays, and immunoblots. Interestingly, 2D216 had minimal, if any, activity on Jurkat T cells but induced cytokine production and surface expression of costimulatory molecules on cells with antigen-presenting functions. A small series of analogs of 2D216 were tested for the ability to enhance a TLR4 ligand-stimulated autologous mixed lymphocyte reaction (MLR). In the MLR, 2E151, N-(4-(2,5-dimethylphenyl)thiazol-2-yl)-4-((4-propylpiperidin-1-yl)sulfonyl)benzamide, was more potent than 2D216. These results indicate that a small molecule that is not a direct PRR agonist can act as a co-adjuvant to an approved adjuvant to enhance human immune responses via a complementary mechanism of action.

Therapeutic Effect of Cyclin-Dependent Kinase 4/6 Inhibitor on Dermal Fibrosis in Murine Models of Systemic Sclerosis.

OBJECTIVE: One of the histologic characteristics of systemic sclerosis (SSc) is an increased number of dermal myofibroblasts, and transforming growth factor ß (TGFß) plays a crucial role in the promotion of myofibroblast differentiation from fibroblasts, leading to dermal fibrosis. This study was undertaken to 1) examine whether inhibition of the cell cycle with a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor suppresses the proliferation of fibroblasts and their differentiation into myofibroblasts, and 2) assess the therapeutic effects of a CDK4/6 inhibitor, administered as monotherapy or in combination with a TGFß receptor (TGFßR) inhibitor, on dermal fibrosis in murine models of SSc. METHODS: Fibroblasts obtained from the skin of patients with SSc were cultured in the presence or absence of TGFß. The effects of palbociclib, a CDK4/6 inhibitor, on fibroblast proliferation and TGFß-induced differentiation into myofibroblasts were examined using bromodeoxyuridine uptake assays as well as immunofluorescence and immunoblotting analyses. Murine models of HOCl- and bleomycin-induced dermal fibrosis were used to study the effect of a CDK4/6 inhibitor on dermal fibrosis, with the CDK4/6 inhibitor treatment administered as monotherapy or in combination with galunisertib, a TGFßR inhibitor. RESULTS: Addition of a CDK4/6 inhibitor to the cell cultures suppressed the proliferation of human dermal SSc fibroblasts and their TGFß-induced differentiation into myofibroblasts, without inhibiting canonical and noncanonical TGFß signals. In murine models of dermal fibrosis, treatment of mice with a CDK4/6 inhibitor decreased dermal thickness and collagen content, as well as dermal fibroblast proliferation and the numbers of myofibroblasts. Combination therapy with the CDK4/6 inhibitor and TGFßR inhibitor resulted in additive antifibrotic effects. Mechanistically, the CDK4/6 inhibitor suppressed the expression of cellular communication network 2 and cadherin-11, which are proteins that have important roles in the development and progression of fibrosis. CONCLUSION: Results of this study demonstrate the therapeutic effect of a CDK4/6 inhibitor on dermal fibrosis when administered as monotherapy or in combination with a TGFßR inhibitor. CDK4/6 inhibitors, including palbociclib used in the present study, may represent novel agents for the treatment of SSc, which, if used in combination with a TGFßR inhibitor, might result in increased efficacy.

Chondroprotective effects of CDK4/6 inhibition via enhanced ubiquitin-dependent degradation of JUN in synovial fibroblasts.

OBJECTIVE: Targeting synovial fibroblasts (SF) using a cyclin-dependent kinase (CDK) 4/6 inhibitor (CDKI) could be a potent therapy for RA via inhibition of proliferation and MMP-3 production. This study was designed to elucidate the mechanism of chondroprotective effects on SFs by CDK 4/6 inhibition. METHODS: CDK4/6 activity was inhibited using CDKI treatment or enhanced by adenoviral gene transduction. Chondroprotective effects were evaluated using a collagen-induced arthritis model (CIA). Gene and protein expression were evaluated with quantitative PCR, ELISA and Western blotting. The binding of nuclear extracts to DNA was assessed with an electrophoresis mobility shift assay. RNA-Seq was performed to identify gene sets affected by CDKI treatment. RESULTS: CDKI attenuated cartilage destruction and MMP-3 production in CIA. In RASFs, CDKI impaired the binding of AP-1 components to DNA and inhibited the production of MMP-1 and MMP-3, which contain the AP-1 binding sequence in their promoter. CDK4/6 protected JUN from proteasome-dependent degradation by inhibiting ubiquitination. The RNA-Seq analysis identified CDKI-sensitive inflammatory genes, which were associated with the pathway of RA-associated genes, cytokine-cytokine receptor interaction and IL-17 signalling. Notably, the AP-1 motif was enriched in these genes. CONCLUSION: The mechanism of chondroprotective effects by CDK4/6 inhibition was achieved by the attenuation of AP-1 transcriptional activity via the impaired stability of JUN. Because the pharmacologic inhibition of CDK4/6 has been established as tolerable in cancer treatment, it could also be beneficial in patients with RA due to its chondroprotective and anti-inflammatory effects.

Arterial and Venous Thrombosis Complicated in COVID-19: A Retrospective Single Center Analysis in Japan.

Background: Thrombosis is a characteristic complication in coronavirus disease 2019 (COVID-19). Since coagulopathy has been observed over the entire clinical course, thrombosis might be a clue to understanding the specific pathology in COVID-19. Currently, there is limited epidemiological data of COVID-19-associated thrombosis in the Japanese population and none regarding variant strains of SARS-CoV-2. Here, we elucidate the risk factors and the pattern of thrombosis in COVID-19 patients. Methods: The patients consecutively admitted to Tokyo Medical and Dental University Hospital with COVID-19 were retrospectively analyzed. SARS-CoV-2 variants of concern/interest (VOC/VOI) carrying the spike protein mutants E484K, N501Y, or L452R were identified by PCR-based analysis. All thrombotic events were diagnosed by clinical symptoms, ultrasonography, and/or radiological tests. Results: Among the 516 patients, 32 patients experienced 42 thromboembolic events. Advanced age, severe respiratory conditions, and several abnormal laboratory markers were associated with the development of thrombosis. While thrombotic events occurred in 13% of the patients with a severe respiratory condition, those events still occurred in 2.5% of the patients who did not require oxygen therapy. Elevated D-dimer and ferritin levels on admission were independent risk factors of thrombosis (adjusted odds ratio 9.39 and 3.11, 95% confidence interval 2.08-42.3, and 1.06-9.17, respectively). Of the thrombotic events, 22 were venous, whereas 20 were arterial. While patients with thrombosis received anticoagulation and antiinflammatory therapies with a higher proportion, the mortality rate, organ dysfunctions, and bleeding complications in these patients were higher than those without thrombosis. The incidence of thrombosis in COVID-19 became less frequent over time, such as during the replacement of the earlier strains of SARS-CoV-2 by VOC/VOI and during increased use of anticoagulatory therapeutics. Conclusion: This study elucidated that elevated D-dimer and ferritin levels are useful biomarkers of thrombosis in COVID-19 patients. The comparable incidence of arterial thrombosis with venous thrombosis and the development of thrombosis in less severe patients required further considerations for the management of Japanese patients with COVID-19. Further studies would be required to identify high-risk populations and establish appropriate interventions for thrombotic complications in COVID-19.