Sphingolipids are important signaling molecules in many biologic processes, but little is known about their organelle-specific roles. Using HeLa cells, we investigated the effects of UV and etoposide-induced apoptosis on the contents of sphingomyelin (SM) and ceramide in subcellular compartments. UV irradiation of HeLa cells increased the levels of SM in all subcellular fractions, but the change was most dramatic in mitochondria. Using diacylglycerol kinase assays to quantify ceramide, we found that the levels of ceramide in mitochondria increased as early as 2 h after UV irradiation and remained elevated at 6 h. The increase in mitochondrial SM and ceramide was inhibited by D609, an inhibitor of sphingomyelinase and SM synthase. The inhibition of sphingolipid production correlated with protection of the mitochondrial transmembrane potential and prevention of cytochrome c release following UV irradiation. In contrast, myriocin, an inhibitor of the de novo ceramide synthesis pathway, only partially suppressed the production of ceramides in mitochondria and cannot suppress UV-induced apoptosis. Fumonicin B1, an inhibitor of ceramide synthase, can only prevent mitochondrial ceramide synthesis and UV-induced apoptosis in a small degree. These results indicate that mitochondrial ceramide production in UV-irradiated HeLa cells is not mediated by the de novo synthesis pathway, but mainly through SM hydrolysis.

Background: With an increase in recent years in the number of people receiving cosmetic facial injection treatments of hyaluronic acid, the incidence of hyaluronic acid embolism has also increased commensurately. Hyaluronic acid embolism leads to serious complications, including blindness, eye and eyelid movement disorders, skin necrosis, and cerebral embolism. However, there is a lack of robust clinical evidence regarding the benefits of treatment for hyaluronic acid embolism by intraarterial thrombolysis therapy. Methods: This study included 24 patients with a decrease in visual acuity and other complications induced by facial hyaluronic acid injection. Patients underwent emergency intraarterial thrombolysis therapy by injection of hyaluronidase (500 to 1500 units) alone or hyaluronidase (750 to 1500 units) combined with urokinase (100,000 to 250,000 units), followed in both cases by a general symptomatic treatment and nutritional therapy. Results: Ten (42 percent) of 24 patients ultimately had improvements to visual acuity, even when the clinical application of the thrombolytic treatments had passed the recommended window for optimal treatment. In all cases, patients’ facial skin necrosis was restored to nearly normal appearance. In addition, the authors found that hyaluronidase combined with urokinase was a more effective therapy than hyaluronidase alone. Conclusions: The authors’ results indicate that intraarterial thrombolysis therapy is beneficial to patients suffering from blindness induced by hyaluronic acid embolism. The therapy was shown to be worthy of clinical application because it alleviated the impairment to patients’ vision and was also beneficial in the recovery from other serious complications, including eye movement disorder, eye edema, headaches, and skin necrosis. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Hypertrophic cardiomyopathy (HCM) is a cardiovascular disease with high heterogeneity. Limited knowledge concerning the genetic background of nearly 40% HCM cases indicates there is a clear need for further investigation to explore the genetic pathogenesis of the disease. In this study, we undertook a whole exome sequencing (WES) approach to identify novel candidate genes and mutations associated with HCM. The cohort consisted of 74 unrelated patients with sporadic HCM (sHCM) previously determined to be negative for mutations in eight sarcomere genes. The results showed that 7 of 74 patients (9.5%) had damaging mutations in 43 known HCM disease genes. Furthermore, after analysis combining the Transmission and De novo Association (TADA) program and the ToppGene program, 10 putative genes gained priority. A thorough review of public databases and related literature revealed that there is strong supporting evidence for most of the genes playing roles in various aspects of heart development. Findings from recent studies suggest that the putative and known disease genes converge on three functional pathways: sarcomere function, calcium signaling and metabolism pathway. This study illustrates the benefit of WES, in combination with rare variant analysis tools, in providing valuable insight into the genetic etiology of a heterogeneous sporadic disease.

B and T lymphocyte attenuator (BTLA) has been recently identified as a new inhibitory receptor of the CD28 superfamily, with similarities to cytotoxic T lymphocyte activation antigen (CTLA)-4 and programmed death (PD)-1. Engagement of BTLA on T lymphocytes can profoundly reduce the T cell receptor (TCR)-mediated activation. In this study, we generated four monoclonal antibodies (mAbs) against human BTLA. Using the produced mAb 8H9, the BTLA molecule was found to distinctly express on many subgroups of immunocytes and show a regulatory expression, which was in accordance with its unique ligand herpes virus entry mediator (HVEM) in the process of T cell activation. In addition, the expression of BTLA was increased in the CD4(+) and CD8(+) T cells of pleural fluid in lung cancer patients. Furthermore, we showed that the BTLA-induced negative signals could be triggered by mAb 7D7. Cross-linking of BTLA with mAb 7D7 suppressed T lymphocyte proliferation, downregulated the expression of T cell activation marker CD25, and inhibited the production of interferon (IFN)-gamma, interleukin (IL)-2, IL-4, and IL-10.