In the peripheral blood leukocytes (PBLs) from the carriers of the human T-lymphotropic virus type-1 (HTLV-1) or the patients with adult T-cell leukemia (ATL), nuclear factor kappaB (NF-κB)-mediated antiapoptotic signals are constitutively activated primarily by the HTLV-1-encoded oncoprotein Tax. Tax interacts with the I κB kinase regulatory subunit NEMO (NF-κB essential modulator) to activate NF-κB, and this interaction is maintained in part by a molecular chaperone, heat-shock protein 90 (HSP90), and its co-chaperone cell division cycle 37 (CDC37). The antibiotic geldanamycin (GA) inhibits HSP90's ATP binding for its proper interaction with client proteins. Administration of a novel water-soluble and less toxic GA derivative, 17-dimethylaminoethylamino-17-demethoxygeldanamycin hydrochloride (17-DMAG), to Tax-expressing ATL-transformed cell lines, C8166 and MT4, induced significant degradation of Tax. 17-DMAG also facilitated growth arrest and cellular apoptosis to C8166 and MT4 and other ATL cell lines, although this treatment has no apparent effects on normal PBLs. 17-DMAG also downregulated Tax-mediated intracellular signals including the activation of NF-κB, activator protein 1 or HTLV-1 long terminal repeat in Tax-transfected HEK293 cells. Oral administration of 17-DMAG to ATL model mice xenografted with lymphomatous transgenic Lck-Tax (Lck proximal promoter-driven Tax transgene) cells or HTLV-1-producing tumor cells dramatically attenuated aggressive infiltration into multiple organs, inhibited de novo viral production and improved survival period. These observations identified 17-DMAG as a promising candidate for the prevention of ATL progression.
Tumor necrosis factor (TNF)-α is a potent mediator of inflammation and is involved in the pathophysiology of chronic kidney disease (CKD). However, the effects of TNF-α inhibition on the progression of kidney fibrosis have not been fully elucidated. We examined the effects of TNF-α inhibition by etanercept (ETN) on kidney inflammation and fibrosis in mice with aristolochic acid (AA) nephropathy as a model of kidney fibrosis. C57BL/6 J mice were administered AA for 4 weeks, followed by a 4-week remodeling period. The mice exhibited kidney fibrosis, functional decline, and albuminuria concomitant with increases in renal mRNA expression of inflammation- and fibrosis-related genes. The 8-week ETN treatment partially but significantly attenuated kidney fibrosis and ameliorated albuminuria without affecting kidney function. These findings were accompanied by significant suppression of interleukin (IL)-1β, IL-6, and collagen types I and III mRNA expression. Moreover, ETN tended to reduce the AA-induced increase in interstitial TUNEL-positive cells with a significant reduction in Bax mRNA expression. Renal phosphorylated p38 MAPK was significantly upregulated by AA but was normalized by ETN. These findings indicate a substantial role for the TNF-α pathway in the pathogenesis of kidney fibrosis and suggest that TNF-α inhibition could become an adjunct therapeutic strategy for CKD with fibrosis.
BackgroundThrombospondin type-1 domain-containing 7A (THSD7A) is a target antigen in idiopathic membranous nephropathy (MN). Patients with THSD7A-associated MN are known to have a high possibility of developing malignancy. However, there are few case reports on THSD7A-associated MN with malignancy, and details of its characteristics have not been clarified thoroughly. Here, we report the case of a 77-year-old male patient who was diagnosed with THSD7A-associated MN after resection of rectal cancer.Case presentationA 77-year-old man who had developed bilateral peripheral edema, persistent proteinuria, and nephrotic syndrome was admitted to our hospital. He was diagnosed with MN based on a renal biopsy 3 years after resection of rectal cancer, and positive staining for THSD7A in both kidney and rectal cancer tissues suggested that these two diseases were related. Furthermore, THSD7A staining of metastatic lymph nodes revealed deposition of THSD7A in the secondary lymph follicles and sinus. Recurrence of rectal cancer was suspected; however, tumor recurrence was not observed on chest and abdominal computed tomography (CT) and colonoscopy. There was no lymph node enlargement. The patient was kept on observation with supportive therapy. Consequently, although nephrotic syndrome persisted, obvious recurrence and metastasis of the primary tumor were not observed.ConclusionThis is the first case in which pathological examination results suggested that THSD7A-associated MN was caused by rectal cancer. Based on the reports of THSD7A-associated MN with malignancy and the pathogenesis of MN, lymph node metastasis may be a risk for cancer-related MN.
Elevated angiotensin-converting enzyme 2 (ACE2) expression in organs that are potential targets of severe acute respiratory syndrome coronavirus 2 may increase the risk of coronavirus disease 2019 (COVID-19) infection. Previous reports show that ACE2 alter its tissue-specific expression patterns under various pathological conditions, including renal diseases. Here, we examined changes in pulmonary ACE2 expression in two mouse chronic kidney disease (CKD) models: adenine-induced (adenine mice) and aristolochic acid-induced (AA mice). We also investigated changes in pulmonary ACE2 expression due to renin–angiotensin system (RAS) blocker (olmesartan) treatment in these mice. Adenine mice showed significant renal functional decline and elevated blood pressure, compared with controls. AA mice also showed significant renal functional decline, compared with vehicles; blood pressure did not differ between groups. Renal ACE2 expression was significantly reduced in adenine mice and AA mice; pulmonary expression was unaffected. Olmesartan attenuated urinary albumin excretion in adenine mice, but did not affect renal or pulmonary ACE2 expression levels. The results suggest that the risk of COVID-19 infection may not be elevated in patients with CKD because of their stable pulmonary ACE2 expression. Moreover, RAS blockers can be used safely in treatment of COVID-19 patients with CKD.
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