👤 Naoya Takayama

Membranous nephropathy (MN) in very elderly patients frequently remains antigen-negative after routine testing, limiting diagnostic precision. Recently, serine protease high temperature requirement protein A1 (HTRA1) has been identified as a novel MN autoantigen. Here, we focused on patients 80 years and older with MN and sought to systematically evaluate this association. Three cohorts of patients with MN were examined under institutional approval, including 157 consecutive all-age series of PLA2R/THSD7A/NELL1/EXT1-negative patients with MN typed by mass spectrometry; 54 PLA2R-negative MN in patients aged 80 years and older assessed by paraffin immunofluorescence; and 45 PLA2R-negative malignancy-associated patients with MN. HTRA1 positivity was determined by paraffin immunofluorescence and/or mass spectrometry. Clinical and histopathologic features were reviewed where available. Proportions were compared using Fisher's exact test. HTRA1 positivity was identified in 1.9% of patients with PLA2R/THSD7A/NELL1/EXT-negative MN, 22.2% of patients 80 years and older, and 6.7% of patients with PLA2R-negative malignancy-associated MN. Compared with the all-age antigen-negative cohort, HTRA1 positivity was significantly enriched in patients aged 80 years (relative risk 11.6; 95% confidence interval 3.4- 39.7). Across all 18 HTRA1-positive cases, mean age was 81.5, 66.7% were male, and 83.3% had nephrotic-range proteinuria. HTRA1 is a common autoantigen in PLA2R-negative MN among very elderly patients, occurring in approximately one in five cases aged 80 years or more. These findings support inclusion of HTRA1 testing in diagnostic evaluation of antigen-negative MN in patients 80 years and older and suggest the existence of an age-linked MN subtype. Show less

Lysophosphatidic acid (LPA) and its receptor LPA1 have been implicated in tissue inflammation and fibrosis; however, their role in mucus overproduction remains unclear. Pulmonary neuroendocrine cells (PNECs), which are rare airway epithelial cells, contribute to mucus overproduction and immune modulation. In this study, we investigated the role of the LPA/LPA1 receptor axis in goblet cell hyperplasia and mucus overproduction, as well as the contribution of PNECs, using a chronic mouse model of bronchial asthma. A chronic mouse model of asthma was established by sensitization and challenge with the house dust mite antigen Dermatophagoides pteronyssinus (Dp), with or without treatment using the LPA1 antagonist AM095. Airway hyperresponsiveness, histopathology, mediator concentrations, and molecular expression in lung homogenate supernatants were evaluated. Lysophospholipid levels and low-molecular-weight metabolites were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Lung LPA 22:5 levels were elevated in Dp-challenged mice. LPA1 receptors were co-localized with PNECs in the lung. Treatment with AM095 reduced goblet cell hyperplasia by inhibiting the production of gamma-aminobutyric acid (GABA) and calcitonin gene-related peptide (CGRP) by PNECs. It also suppressed arginase 1 and polyamine production in CGRP-stimulated M2 macrophages. AM095 did not affect eosinophil extracellular trap (EET) formation in bronchoalveolar lavage fluid, which activates PNECs. The LPA/LPA1 axis promotes goblet cell hyperplasia through PNEC activation and downstream GABA and CGRP signaling in a chronic asthma model. LPA1 antagonism may represent a potential therapeutic strategy for controlling mucus overproduction in asthma. Show less

Platelet-rich plasma (PRP), which is prepared by concentrating platelets in autologous blood, shows efficacy in chronic skin wounds via multiple growth factors. However, it exhibits heterogeneity across patients, leading to unstable therapeutic efficacy. Human induced pluripotent stem cell (iPSC)-derived megakaryocytes and platelets (iMPs) are capable of providing a stable supply, holding promise as materials for novel platelet concentrate-based therapies. In this context, we evaluated the effect of iMPs on wound healing and validated lyophilization for clinical applications. The growth factors released by activated iMPs were measured. The effect of the administration of iMPs on human fibroblasts and human umbilical vein endothelial cells (HUVECs) was investigated in vitro. iMPs were applied to dorsal skin defects of diabetic mice to assess the wound closure rate and quantify collagen deposition and angiogenesis. Following the storage of freeze-dried iMPs (FD-iMPs) for three months, the stability of growth factors and their efficacy in animal models were determined. Multiple growth factors that promote wound healing were detected in activated iMPs. iMPs specifically released FGF2 and exhibited a superior enhancement of HUVEC proliferation compared to PRP. Moreover, an RNA-seq analysis revealed that iMPs induce polarization to stalk cells and enhance ANGPTL4 gene expression in HUVECs. Animal studies demonstrated that iMPs promoted wound closure and angiogenesis in chronic wounds caused by diabetes. We also confirmed the long-term stability of growth factors in FD-iMPs and their comparable effects to those of original iMPs in the animal model. Our study demonstrates that iMPs promote angiogenesis and wound healing through the activation of vascular endothelial cells. iMPs exhibited more effectiveness than PRP, an effect attributed to the exclusive presence of specific factors including FGF2. Lyophilization enabled the long-term maintenance of the composition of the growth factors and efficacy of the iMPs, therefore contributing to stable supply for clinical application. These findings suggest that iMPs provide a novel treatment for chronic wounds. Show less

We previously reported that combined therapy with epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) osimertinib and AXL inhibitor ONO-7475 is effective in preventing the survival of drug-tolerant cells in high-AXL-expressing EGFR-mutated non-small cell lung cancer (NSCLC) cells. Nevertheless, certain residual cells are anticipated to eventually develop acquired resistance to this combination therapy. In this study, we attempted to establish a multidrug combination therapy from the first-line setting to overcome resistance to this combination therapy in high-AXL-expressing EGFR-mutated NSCLC. siRNA screening assay showed that fibroblast growth factor receptor 1 (FGFR1) knockdown induced pronounced inhibition of cell viability in the presence of the osimertinib-ONO-7475 combination, which activates FGFR1 by upregulating FGF2 via the c-Myc pathway. Cell-based assays showed that triple therapy with osimertinib, ONO-7475, and the FGFR inhibitor BGJ398 significantly increased apoptosis by increasing expression of proapoptotic factor Bim and reduced cell viability compared with that observed for the osimertinib-ONO-7475 therapy. Xenograft models showed that triple therapy considerably suppressed tumor regrowth. A novel therapeutic strategy of additional initial FGFR1 inhibition may be highly effective in suppressing the emergence of osimertinib- and ONO-7475-resistant cells. Show less

Multiple osteochondroma (MO) is an autosomal dominant skeletal disorder characterized by the formation of multiple osteochondromas, and exostosin-1 (EXT1) and exostosin-2 (EXT2) are major causative genes in MO. In this study, we evaluated the genetic backgrounds and mutational patterns in Japanese families with MO. We evaluated 112 patients in 71 families with MO. Genomic DNA was isolated from peripheral blood leucocytes. The exons and exon/intron junctions of EXT1 and EXT2 were directly sequenced after PCR amplification. Fifty-two mutations in 47 families with MO in either EXT1 or EXT2, and 42.3% (22/52) of mutations were novel mutations. Twenty-nine families (40.8%) had mutations in EXT1, and 15 families (21.1%) had mutations in EXT2. Interestingly, three families (4.2%) had mutations in both EXT1 and EXT2. Twenty-four families (33.8%) did not exhibit mutations in either EXT1 or EXT2. With regard to the types of mutations identified, 59.6% of mutations were inactivating mutations, and 38.5% of mutations were missense mutations. We found that the prevalence of EXT1 mutations was greater than that of EXT2 mutations in Japanese MO families. Additionally, we identified 22 novel EXT1 and EXT2 mutations in this Japanese MO cohort. This study represents the variety of genotype in MO. Show less