No abstract

Objectives. Aberrant NLRP3 inflammasome activation has been demonstrated in rheumatoid arthritis (RA), which may contribute to debilitating inflammation and bone destruction. Here, we explored the efficacy of the potent TGF-b-activated kinase-1 (TAK1) inhibitor LL-Z1640-2 (LLZ) on joint inflammation and bone destruction in collagen-induced arthritis (CIA). Methods. LL-Z1640-2 was administered every other day in CIA mice. Clinical and histological evaluation was performed. Priming and activation of NLRP3 inflammasome and osteoclastogenic activity were assessed. Results. NLRP3 inflammasome formation was observed in synovial macrophages and osteoclasts (OCs) in CIA mice. TACE and RANKL were also overexpressed in synovial macrophages and fibroblasts, respectively, in the CIA joints. Treatment with LLZ mitigated all the above changes. As a result, LLZ markedly suppressed synovial hypertrophy and pannus formation to alleviate pain and inflammation in CIA mice. LLZ could block the priming and activation of NLRP3 inflammasome in RAW264.7 macrophage cell line, primary bone marrow macrophages and OCs upon treatment with LPS followed by ATP, thereby suppressing their IL-1b production. LLZ also suppressed LPS-induced production of TACE and TNF-a in bone marrow macrophages and abolished IL-1binduced production of MMP-3, IL-6 and RANKL in synovial fibroblasts. In addition, LLZ directly inhibits RANKL-mediated OC formation and activation. Conclusion. TAK1 inhibition with LLZ

Disseminated Cryptosporidium infection results in manifestations similar to those of graft‐versus‐host disease (GVHD), which hampers the detection of Cryptosporidium infection after allogeneic hematopoietic stem cell transplantation. Surveillance of oocysts on the surface of intestinal epithelial cells is needed for early and appropriate detection of Cryptosporidium infection in transplant recipients on immunosuppressants with severe intractable diarrhea. We present the first case of Cryptosporidium meleagridis infection in Japan after allogeneic cord blood transplantation.

This study was undertaken to identify baseline conditions and triggering factors for skeletal‐related events (SRE) in multiple myeloma (MM) patients treated with denosumab. During the median follow‐up of 17 months, SRE occurred in 6 out of 52 newly diagnosed patients and in 5 out of 23 relapsed/refractory patients. Bone fractures occurred by falling down due to orthostatic hypotension and/or muscle weakness in three out of four cases with amyloid light‐chain (AL) amyloidosis. A loss of balance and falling down appear to be triggering factors for SRE, especially in frail MM patients with AL amyloidosis, indicating the importance of retaining physical functions to prevent SRE.

Multiple myeloma (MM) preferentially expands and acquires drug resistance in bone marrow. We herein examined the role of histone deacetylase 1 (HDAC1) in the constitutive activation of the master transcription factor IRF4 and the pro-survival mediator PIM2 kinase in MM cells. The knockdown or inhibition of HDAC1 by the class I HDAC inhibitor MS-275 reduced the basal expression of IRF4 and PIM2 in MM cells. Mechanistically, the inhibition of HDAC1 decreased IRF4 transcription through histone hyperacetylation and inhibiting the recruitment of RNA polymerase II at the IRF4 locus, thereby reducing IRF4-targeting genes, including PIM2. In addition to the transcriptional regulation of PIM2 by the HDAC1-IRF4 axis, PIM2 was markedly up-regulated by external stimuli from bone marrow stromal cells and IL-6. Up-regulated PIM2 contributed to the attenuation of the cytotoxic effects of MS-275. Class I HDAC and PIM kinase inhibitors cooperatively suppressed MM cell growth in the presence of IL-6 and in vivo. Therefore, the present results demonstrate the potential of the simultaneous targeting of the intrinsic HDAC1-IRF4 axis plus externally activated PIM2 as an efficient therapeutic option for MM fostered in bone marrow.