Objective-The delivery of autologous progenitor cells into ischemic tissue of patients is emerging as a novel therapeutic option. Here, we report the potential impact of cultured adipose tissue-derived cells (ADSC) on angiogenic cell therapy. Method and Results-ADSC were isolated from C57Bl/6 mouse inguinal adipose tissue and showed high expression of ScaI and CD44, but not c-kit, Lin, CD34, CD45, CD11b, and CD31, compatible with that of mesenchymal stem cells from bone marrow. In coculture conditions with ADSC and human aortic endothelial cells (ECs) under treatment with growth factors, ADSC significantly increased EC viability, migration and tube formation mainly through secretion of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). At 4 weeks after transplantation of ADSC into the ischemic mouse hindlimb, the angiogenic scores were improved in the ADSC-treated group, which were evaluated with blood flow by laser Doppler imaging (LDI) and capillary density by immunostaining with anti-CD31 antibody. However, injected ADSC did not correspond to CD31, von Willebrand factor, and ␣-smooth muscle actin-positive cells in ischemic tissue.
Recent clinical studies suggest that several antihypertensive drugs, especially angiotensin-converting enzyme inhibitors, reduced bone fractures. To clarify the relationship between hypertension and osteoporosis, we focused on the role of angiotensin II (Ang II) on bone metabolism. In bone marrow-derived mononuclear cells, Ang II (1x10(-6) M) significantly increased tartrate-resistant acid phosphatase (TRAP) -positive multinuclear osteoclasts. Of importance, Ang II significantly induced the expression of receptor activator of NF-kappaB ligand (RANKL) in osteoblasts, leading to the activation of osteoclasts, whereas these effects were completely blocked by an Ang II type 1 receptor blockade (olmesartan) and mitogen-activated protein kinase kinase inhibitors. In a rat ovariectomy model of estrogen deficiency, administration of Ang II (200 ng/kg/min) accelerated the increase in TRAP activity, accompanied by a significant decrease in bone density and an increase in urinary deoxypyridinoline. In hypertensive rats, treatment with olmesartan attenuated the ovariectomy-induced decrease in bone density and increase in TRAP activity and urinary deoxypyridinoline. Furthermore, in wild-type mice ovariectomy with five-sixths nephrectomy decreased bone volume by microcomputed tomography, whereas these change was not detect in Ang II type 1a receptor-deficient mice. Overall, Ang II accelerates osteoporosis by activating osteoclasts via RANKL induction. Blockade of Ang II might become a novel therapeutic approach to prevent osteoporosis in hypertensive patients.
Adult stem cells hold great promise for use in tissue repair and regeneration, and the delivery of autologous progenitor cells into ischemic tissue is emerging as a novel therapeutic option. We and others have recently demonstrated the potential impact of adipose tissue-derived stromal cells (ADSC) on regenerative cell therapy for ischemic diseases. The main benefit of ADSC is that they can be easily harvested from patients by a simple, minimally invasive method and also easily cultured. Cultured ADSC can be induced to differentiate into not only adipocytes, but also bone, neurons or endothelial cells in certain conditions. Interestingly, they secrete a number of angiogenesis-related cytokines, such as vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF), which might be suitable for regenerative cell therapy for ischemic diseases. In the ischemic mouse hindlimb, the angiogenic score was improved in the ADSC-treated group. Moreover, recent reports demonstrated that these ADSC can also be induced to differentiate into cardiac myocytes. These adipose tissuederived cells have potential in angiogenic cell therapy for ischemic disease, and might be applied for regenerative cell therapy instead of bone marrow cells in the near future.
Background-Subarachnoid hemorrhage caused by the rupture of cerebral aneurysm (CA) remains a life-threatening disease despite recent diagnostic and therapeutic advancements. Recent studies strongly suggest the active participation of macrophage-mediated chronic inflammatory response in the pathogenesis of CA. We examined the role of nuclear factor-B (NF-B) in the pathogenesis of CA formation in this study. Methods and Results-In experimentally induced CAs in rats, NF-B was activated in cerebral arterial walls in the early stage of aneurysm formation with upregulated expression of downstream genes. NF-B p50 subunitdeficient mice showed a decreased incidence of CA formation with less macrophage infiltration into the arterial wall. NF-B decoy oligodeoxynucleotide also prevented CA formation when it was administered at the early stage of aneurysm formation in rats. Macrophage infiltration and expression of downstream genes were dramatically inhibited by NF-B decoy oligodeoxynucleotide. In human CA walls, NF-B also was activated, especially in the intima. Conclusions-Our data indicate that NF-B plays a crucial role as a key regulator in the initiation of CA development by inducing some inflammatory genes related to macrophage recruitment and activation. NF-B may represent a therapeutic target of a novel medical treatment for CA.
Brown adipocytes can differentiate from white fat progenitor cells in mice exposed to cold or β3-adrenergic stimulation, and this process is regulated by a microRNA that regulates the expression of Hoxc8, a master regulator of brown adipogenesis.
Antibodies against the receptor-binding-domain of the SARS-CoV-2 spike protein prevent SARS-CoV-2 infection. However, the effects of antibodies against other spike protein domains are largely unknown. Here, we screened a series of anti-spike monoclonal antibodies from COVID-19 patients, and found that some of antibodies against the N-terminal-domain (NTD) induced the open conformation of receptor binding domain (RBD) and thus enhanced the binding capacity of the spike protein to ACE2 and infectivity of SARS-CoV-2. Mutational analysis revealed that all the infectivity-enhancing antibodies recognized a specific site on the NTD. Structural analysis demonstrated that all the infectivity-enhancing antibodies bound to NTD in a similar manner. The antibodies against this infectivity-enhancing site were detected at high levels in severe patients. Moreover, we identified antibodies against the infectivity-enhancing site in uninfected donors, albeit at a lower frequency. These findings demonstrate that not only neutralizing antibodies but also enhancing antibodies are produced during SARS-CoV-2 infection.
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