Role of transient receptor potential vanilloid 4 in therapeutic antifibrotic effects of pirfenidone.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fatal lung disorder characterized by aberrant extracellular matrix deposition in the interstitium. Pirfenidone is an antifibrotic agent used to treat patients with IPF. Pirfenidone shows a pleiotropic mode of action, but its underlying antifibrotic mechanism is unclear. Transient receptor potential vanilloid 4 (TRPV4), which is a mechanosensitive calcium channel, was recently shown to be related to pulmonary fibrosis. To clarify the antifibrotic mechanisms of pirfenidone, we investigated whether TRPV4 blockade has a pharmacological effect in a murine model of pulmonary fibrosis and whether pirfenidone contributes to suppression of TRPV4. Our synthetic TRPV4 antagonist and pirfenidone treatment attenuated lung injury in the bleomycin mouse model. TRPV4-mediated increases in intracellular calcium were inhibited by pirfenidone. In addition, TRPV4-stimulated interleukin-8 release from cells was reduced and a delay in cell migration was abolished by pirfenidone. Furthermore, pirfenidone decreased TRPV4 endogenous ligands in bleomycin-administered mouse lungs and their production by microsomes of human lungs. We found TRPV4 expression in the bronchiolar and alveolar epithelium and activated fibroblasts of the lungs in patients with IPF. Finally, we showed that changes in forced vital capacity of patients with IPF treated with pirfenidone were significantly correlated with metabolite levels of TRPV4 endogenous ligands in bronchoalveolar lavage fluid. These results suggest that the antifibrotic action of pirfenidone is partly mediated by TRPV4 and that TRPV4 endogenous ligands in bronchoalveolar lavage fluid may be biomarkers for distinguishing responders to pirfenidone.

Inhibition of dengue virus infection by 1-stearoyl-2-arachidonoyl-phosphatidylinositol in vitro.

Dengue fever is an acute febrile infectious disease caused by dengue virus (DENV). Despite the significant public health concerns posed by DENV, there are currently no effective anti-DENV therapeutic agents. To develop such drugs, a better understanding of the detailed mechanisms of DENV infection is needed. Both lipid metabolism and lipid synthesis are activated in DENV-infected cells, so we used lipid screening to identify potential antiviral lipid molecules. We identified 1-stearoyl-2-arachidonoyl-phosphatidylinositol (SAPI), which is the most abundant endogenous phosphatidylinositol (PI) molecular species, as an anti-DENV lipid molecule. SAPI suppressed the cytopathic effects induced by DENV2 infection as well as the replication of all DENV serotypes without inhibiting the entry of DENV2 into host cells. However, no other PI molecular species or PI metabolites, including lysophosphatidylinositols and phosphoinositides, displayed anti-DENV2 activity. Furthermore, SAPI suppressed the production of DENV2 infection-induced cytokines and chemokines, including C-C motif chemokine ligand (CCL)5, CCL20, C-X-C chemokine ligand 8, IL-6, and IFN-ß. SAPI also suppressed the TNF-α production induced by LPS stimulation in macrophage cells differentiated from THP-1 cells. Our results demonstrated that SAPI is an endogenous inhibitor of DENV and modulated inflammatory responses in DENV2-infected cells, at least in part via TLR 4.-Sanaki, T., Wakabayashi, M., Yoshioka, T., Yoshida, R., Shishido, T., Hall, W. W., Sawa, H., Sato, A. Inhibition of dengue virus infection by 1-stearoyl-2-arachidonoyl-phosphatidylinositol in vitro.

Decreases in 15-lipoxygenase metabolites in Olmsted syndrome model rats.

BACKGROUND: Olmsted syndrome (OS) is a congenital dermatosis characterized by palmoplantar keratoderma and periorificial keratotic plaque. TRPV3 (transient receptor potential vanilloid subtype 3) encodes a thermosensitive Ca2+ channel and is the causative gene of OS. However, the molecular mechanism that causes the pathological development of OS is unclear. OBJECTIVE: We aimed to investigate the molecular mechanisms underlying OS pathology from the perspective of lipid metabolism. METHODS: Comprehensive lipidomics and microarray analyses were conducted on tissue samples from a non-lesional skin area of OS model rats (Ht rats) and from wild type (WT) rats as the control. RESULTS: Infiltration of leukocytes such as eosinophils and neutrophils and an increase in the fibrotic region were detected in the unaffected skin area of Ht rats compared with the WT rats. Among about 600 lipid species examined, the levels of 15-lipoxygenase (LOX) metabolites, the precursors of anti-inflammatory and pro-resolving lipid mediators, and dihydroceramides decreased by ≥16-fold in Ht rats compared with WT rats. Consistent with the decreases in the 15-LOX metabolites, expression levels of the genes that encode the 15-LOXs, Alox15 and Alox15b, were largely reduced. Conversely, increased expression levels were detected of Il36b, Ccl20, Cxcl1, and Cxcl2, which encode cytokines/chemokines, and S100a8 and S100a9, which encode the Ca2+ binding proteins that are implicated in epidermal proliferation. CONCLUSION: The pro-inflammatory state in the unaffected skin of Ht rats caused by decreases in 15-LOX metabolites and increases in cytokines/chemokines may contribute to the pathogenesis of OS.

Histological analyses by matrix-assisted laser desorption/ionization-imaging mass spectrometry reveal differential localization of sphingomyelin molecular species regulated by particular ceramide synthase in mouse brains.

Sphingomyelin (SM) is synthesized by SM synthase (SMS) from ceramide (Cer). SM regulates signaling pathways and maintains organ structure. SM comprises a sphingoid base and differing lengths of acyl-chains, but the importance of its various forms and regulatory synthases is not known. It has been reported that Cer synthase (CerS) has restricted substrate specificity, whereas SMS has no specificity for different lengths of acyl-chains. We hypothesized that the distribution of each SM molecular species was regulated by expression of the CerS family. Thus, we compared the distribution of SM species and CerS mRNA expression using molecular imaging. Spatial distribution of each SM molecular species was investigated using ultra-high-resolution imaging mass spectrometry (IMS). IMS revealed that distribution of SM molecular species varied according to the lengths of acyl-chains found in each brain section. Furthermore, a combination study using in situ hybridization and IMS revealed the spatial expression of CerS1 to be associated with the localization of SM (d18:1/18:0) in cell body-rich gray matter, and CerS2 to be associated with SM (d18:1/24:1) in myelin-rich white matter. Our study is the first comparison of spatial distribution between SM molecular species and CerS isoforms, and revealed their distinct association in the brain. These observations were demonstrated by suppression of CerS2 using siRNA in HepG2 cells; that is, siRNA for CerS2 specifically decreased C22 very long-chain fatty acid (VLCFA)- and C24 VLCFA-containing SMs. Thus, histological analyses of SM species by IMS could be a useful approach to consider their molecular function and regulative mechanism.

A comparison of outcomes and complications of totally implantable access port through the internal jugular vein versus the subclavian vein.

Totally implantable access ports (TIAPs) are generally used in oncology. Few studies have addressed complications associated with the insertion site. A total of 233 consecutive oncology patients were enrolled to receive TIAP inserts via internal jugular vein (IJV) or subclavian vein (SV). Data on clinicopathologic parameters and early/late complications were retrospectively collected. No differences were found early and late complication rates. Catheter injury was observed more frequently in the IJV group (2.9%) than in the SV group (1.0%) without statistical significance. Multivariate logistic regression analysis showed that age, switch to palliative use of TIAP, and the distribution of diseases (low risk in patients with colorectal cancer) were independent risk factors for determining complications. In conclusion, TIAP insertion site showed no impact on the early and late complication rates. Catheter injury appears to occur at the same frequency with both approaches. Therefore, medical doctors may choose their preferred puncture site when performing TIAP insertion.