Systemic administration of clinical-grade multilineage-differentiating stress-enduring cells ameliorates hypoxic-ischemic brain injury in neonatal rats.

Multilineage-differentiating stress-enduring (Muse) cells are endogenous reparative pluripotent stem cells present in the bone marrow, peripheral blood, and organ connective tissues. We assessed the homing and therapeutic effects of systemically administered nafimestrocel, a clinical-grade human Muse cell-based product, without immunosuppressants in a neonatal hypoxic-ischemic (HI) rat model. HI injury was induced on postnatal day 7 (P7) and was confirmed by T2-weighted magnetic resonance imaging on P10. HI rats received a single dose nafimestrocel (1 × 106 cells/body) or Hank's balanced salt solution (vehicle group) intravenously at either three days (on P10; M3 group) or seven days (on P14; M7 group) after HI insult. Radioisotope experiment demonstrated the homing of chromium-51-labeled nafimestrocel to the both cerebral hemispheres. The cylinder test (M3 and M7 groups) and open-field test (M7 group) showed significant amelioration of paralysis and hyperactivity at five weeks of age compared with those in the vehicle group. Nafimestrocel did not cause adverse events such as death or pathological changes in the lung at ten weeks in the both groups. Nafimestrocel attenuated the production of tumor necrosis factor-α and inducible nitric oxide synthase from activated cultured microglia in vitro. These results demonstrate the potential therapeutic benefits and safety of nafimestrocel.

Anti-KIF20B autoantibodies in systemic autoimmune rheumatic diseases: Their high prevalence in systemic lupus erythematosus.

The kinesin superfamily protein 20B (KIF20B), also known as M-phase phosphoprotein-1, is a plus-end-directed motor enzyme for cytokinesis. Anti-KIF20B antibodies have been reported in idiopathic ataxia, but no previous studies have examined anti-KIF20B antibodies in systemic autoimmune rheumatic diseases (SARDs). We aimed to establish methods for detecting anti-KIF20B antibodies and to investigate the clinical significance of these antibodies in SARDs. Serum samples from 597 patients with various SARDs and 46 healthy controls (HCs) were included. Fifty-nine samples that had been examined by immunoprecipitation using the recombinant KIF20B protein produced by in vitro transcription/translation were used for establishing the ELISA cutoff with the same recombinant protein for measuring the anti-KIF20B antibodies. The ELISA performed well, showing close agreement with the immunoprecipitation results (Cohen's κ >0.8). The ELISA results for 643 samples showed the prevalence of anti-KIF20B to be higher in the systemic lupus erythematosus (SLE) patients than in the HCs (18/89 vs. 3/46, P = 0.045). Since no SARD other than SLE had higher frequencies of anti-KIF20B antibodies than those of the HCs, we investigated the clinical characteristics of anti-KIF20B antibody-positive cases in SLE. The score on the SLE Disease Activity Index-2000 (SLEDAI-2K) was significantly higher for the anti-KIF20B-positive SLE patients than for the anti-KIF20B-negative SLE patients (P = 0.013). In a multivariate regression analysis of the anti-single-stranded deoxyribonucleic acid, anti-double-stranded deoxyribonucleic acid, and anti-KIF20B antibodies, the presence of anti-KIF20B antibody was significantly associated with high SLEDAI-2K scores (P = 0.003). Anti-KIF20B antibodies were found in ~20% of patients with SLE and were associated with high SLEDAI-2K scores. Much larger cohort and longitudinal studies are needed to confirm the association between anti-KIF20B antibodies and SLE.

Two novel anti-aminoacyl tRNA synthetase antibodies: Autoantibodies against cysteinyl-tRNA synthetase and valyl-tRNA synthetase.

Anti-aminoacyl-tRNA synthetase (anti-ARS) antibodies are useful for identifying a clinical subset of patients with inflammatory myopathies. Since the myositis of anti-ARS-positive patients is characterized by a unique set of non-myopathic manifestations, including interstitial lung disease, mechanic's hands, and arthralgia, the patients are classified as having anti-synthetase syndrome. Autoantibodies have been identified to eight kinds of ARSs. Of the other 12 ARSs, eight are components of the "OJ" multi-synthetase complex. Autoantibodies to the four remaining ARSs (CysARS, ValARS, SerARS, and TrpARS) have not been reported to be present in patients with inflammatory myopathies. In this study, we first screened samples from more than 300 Japanese patients majorly consisting of those with dermatomyositis (DM) by our established in-house ELISA to find autoantibodies against the four ARSs described above. Since sera from two DM patients specifically reacted to CysARS or ValARS, we determined their reactivities by immunoprecipitation (IP) with the corresponding recombinant proteins and IP-Western blotting with cellular extract. One patient had several features found in anti-synthetase syndrome, but the other did not. The clinical differences among the various anti-ARS antibodies should be explored in a future work.

Haptoglobin Regulates Macrophage/Microglia-Induced Inflammation and Prevents Ischemic Brain Damage Via Binding to HMGB1.

Background HMGB1 (high-mobility group box 1) is known to worsen the functional prognosis after cerebral ischemia. Hp (haptoglobin) binds and sequesters HMGB1. Furthermore, Hp-HMGB1 complexes are rapidly cleared by scavenger receptors on macrophages/microglia and modulate polarization of macrophages/microglia toward the M2 phenotype. Therefore, Hp may prevent aggravation by HMGB1 after cerebral ischemia and promote tissue repair by M2 macrophages/microglia. The aim of this study was to investigate the effects of Hp on ischemic brain damage induced by a high systemic HMGB1 level in mice subjected to 4 hours of middle cerebral artery occlusion (MCAO). Methods and Results One day after MCAO, Hp was administered intraperitoneally at a dose of 20 or 200 U/kg once daily for 7 days. Neurological scores, motor coordination, and plasma HMGB1 levels were measured 1, 3, and 7 days after MCAO. Expression of M1 and M2 macrophage/microglia markers, such as CD16/32 and CD206, were evaluated by immunostaining 7 days after MCAO. Treatment with Hp for 7 days improved the neurological score, motor coordination, and survival and prevented brain damage after MCAO. The systemic HMGB1 level increased 1 to 7 days after MCAO and was higher at 7 days than at day 1. Hp significantly decreased the systemic HMGB1 level and increased the M2 phenotype when compared with the M1 phenotype after MCAO. Conclusions Hp improved functional outcomes, including survival, motor function, and brain damage by binding to HMGB1 and modulating the polarization of macrophages/microglia. Hp may be an effective option in the treatment of cerebral ischemia.