Chlamydia trachomatis Infection of Endocervical Epithelial Cells Enhances Early HIV Transmission Events

Chlamydia trachomatis causes a predominantly asymptomatic, but generally inflammatory, genital infection that is associated with an increased risk for HIV acquisition. Endocervical epithelial cells provide the major niche for this obligate intracellular bacterium in women, and the endocervix is also a tissue in which HIV transmission can occur. The mechanism by which CT infection enhances HIV susceptibility at this site, however, is not well understood. Utilizing the A2EN immortalized endocervical epithelial cell line grown on cell culture inserts, we evaluated the direct role that CT-infected epithelial cells play in facilitating HIV transmission events. We determined that CT infection significantly enhanced the apical-to-basolateral migration of cell-associated, but not cell-free, HIV_BaL, a CCR5-tropic strain of virus, across the endocervical epithelial barrier. We also established that basolateral supernatants from CT-infected A2EN cells significantly enhanced HIV replication in peripheral mononuclear cells and a CCR5+ T cell line. These results suggest that CT infection of endocervical epithelial cells could facilitate both HIV crossing the mucosal barrier and subsequent infection or replication in underlying target cells. Our studies provide a mechanism by which this common STI could potentially promote the establishment of founder virus populations and the maintenance of local HIV reservoirs in the endocervix. Development of an HIV/STI co-infection model also provides a tool to further explore the role of other sexually transmitted infections in enhancing HIV acquisition.     

Formin-like 1 (FMNL1) Is Regulated by N-terminal Myristoylation and Induces Polarized Membrane Blebbing

The formin protein formin-like 1 (FMNL1) is highly restrictedly expressed in hematopoietic lineage-derived cells and has been previously identified as a tumor-associated antigen. However, function and regulation of FMNL1 are not well defined. We have identified a novel splice variant (FMNL1γ) containing an intron retention at the C terminus affecting the diaphanous autoinhibitory domain (DAD). FMNL1γ is specifically located at the cell membrane and cortex in diverse cell lines. Similar localization of FMNL1 was observed for a mutant lacking the DAD domain (FMNL1ΔDAD), indicating that deregulation of autoinhibition is effective in FMNL1γ. Expression of both FMNL1γ and FMNL1ΔDAD induces polarized nonapoptotic blebbing that is dependent on N-terminal myristoylation of FMNL1 but independent of Src and ROCK activity. Thus, our results describe N-myristoylation as a regulative mechanism of FMNL1 responsible for membrane trafficking potentially involved in a diversity of polarized processes of hematopoietic lineage-derived cells.     

Galectin-1-Induced Autophagy Facilitates Cisplatin Resistance of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers in Taiwan. Although chemotherapy is the primary treatment for HCC patients, drug resistance often leads to clinical failure. Galectin-1 is a beta-galactoside binding lectin which is up-regulated in HCC patients and promotes tumor growth by mediating cancer cell adhesion, migration and proliferation, but its role in chemoresistance of HCC is poorly understood. In this study we found that galectin-1 is able to lead to chemoresistance against cisplatin treatment, and subsequent inhibition has reversed the effect of cell death in HCC cells. Moreover, galectin-1 was found to induce autophagic flux in HCC cells. Inhibition of autophagy by inhibitors or knockdown of Atg5 cancels galectin-1-induced cisplatin resistance in HCC cells. Increase of mitophagy triggered by galectin-1 was found to reduce the mitochondrial potential loss and apoptosis induced by cisplatin treatment. Finally, using an in situ hepatoma mouse model, we clearly demonstrated that inhibition of galectin-1 by thiodigalactoside could significantly augment the anti-HCC effect of cisplatin. Taken together, our findings offer a new insight into the chemoresistance galectin-1 causes against cisplatin treatment, and points to a potential approach to improve the efficacy of cisplatin in the treatment of HCC patients.     

Carbonic anhydrase inhibitors: Inhibition of the tumor-associated isozymes IX and XII with polyfluorinated aromatic/heterocyclic sulfonamides

The tumor-associated transmembrane carbonic anhydrase (CA, EC 4.2.1.1) isozymes IX (CA IX) and XII (CA XII) are involved in acidification of hypoxic tumors, a process correlated with poor prognosis and clinical outcome of patients harboring such tumors. This process may be reversed by inhibiting these enzymes with potent sulfonamide/sulfamate inhibitors. A series of such aromatic/heterocyclic sulfonamides incorporating 2,3,5,6-tetrafluorobenzoyl-, 2,3,5,6-tetrafluoro- phenylsulfonyl- and pentafluorophenylureido moieties has been investigated for its interaction with the catalytic domain of the human isozymes hCA IX and hCA XII. Some of these compounds showed excellent inhibitory properties against both isozymes IX and XII, with several subnanomolar inhibitors detected for the first time. These sulfonamides may constitute valuable candidates for the development of novel antitumor therapies based on the inhibition of such tumor-associated CA isozymes.     

Prenatal diagnosis of Pallister-Killian syndrome and literature review

Pallister-Killian syndrome (PKS) is a rare sporadic genetic disorder usually caused by mosaicism of an extra isochromosome of 12p (i(12p)). This retrospective study analysed the prenatal ultrasound manifestations and molecular and cytogenetic results of five PKS foetuses. Samples of amniotic fluid and/or cord blood, skin biopsy and placenta were collected. Conventional karyotyping and single nucleotide polymorphism array (SNP array) were performed on all the amniotic fluid or cord blood samples. Copy number variants sequencing (CNV-seq) and fluorescence in situ hybridization (FISH) were also used for the validation for one foetus. All the five foetuses were from pregnancies with advanced parental age. Two foetuses involved structural abnormalities and one foetus had only soft markers, all of which included increased nuchal translucency. The rest two foetuses had normal ultrasounds in the second trimester, which has rarely been reported before. The karyotype revealed typical i(12p) in four cases and a small supernumerary marker chromosome consisting of 12p and 20p in the remaining one case. The proportion of cells with i(12p) ranged from 0 to 100% in cultural cells, while SNP array results suggested 2−4 copies of 12p. For one foetus, metaphase FISH showed normal results, but the interphase FISH suggested cell lines with two, three and four copies of 12p in the amniotic fluid. Advanced parental age may be an important risk factor for PKS, and there were no typical ultrasound manifestations related to PKS. A combination of karyotype analysis and molecular diagnosis is an effective method for the diagnosis of PKS.     

Ultrastruttura della cellula apicale di Halopteris scoparia (L.) Sauvageau (Phaeophyceae,Sphacelariales)

Abstract

Ultrastructure of the apical cell of Halopteris scoparia (L.) Sauvageau (Phaeophyceae, Sphacelariales). - The ultrastructure of resting apical cells of Halopteris scoparia (L.) Sauvageau from material collected in December is described. The cytoplasm is higly vacuolated with lipids, poliphenolic substances and polisaccharides occurring inside the vacuoles (the classic « physodes »).

Two cell organelles are prominently active at this stage: conspicuosly hypertrophic dictyosomes and the budding endoplasmic reticulum. Both light and electron microscope observations show that the cell wall has an outer stratification and inner discontinuous thickenings, the constituent material of which is uniformerly dispersed.

The above observations point out that the apical cell of Halopteris scoparia at this stage of its life cycle is engaged in an elaboration of vacuolar and parietal substances which will be therefore readly available at the outset of the growing season.