Population genomics of the southern Caspian Sea Vobla Rutilus lacustris

Hydrobiologia - The genus Rutilus is widespread in the western and central Palearctic region. In the Caspian Sea, the taxonomic status of different populations of Rutilus lacustris has...     

Resveratrol depletes mitochondrial DNA and inhibition of autophagy enhances resveratrol-induced caspase activation

We recently demonstrated that resveratrol induces caspase-dependent apoptosis in multiple cancer cell types. Whether apoptosis is also regulated by other cell death mechanisms such as autophagy is not clearly defined. Here we show that inhibition of autophagy enhanced resveratrol-induced caspase activation and apoptosis. Resveratrol inhibited colony formation and cell proliferation in multiple cancer cell types. Resveratrol treatment induced accumulation of LC3-II, which is a key marker for autophagy. Pretreatment with 3-methyladenine (3-MA), an autophagy inhibitor, increased resveratrol-mediated caspase activation and cell death in breast and colon cancer cells. Inhibition of autophagy by silencing key autophagy regulators such as ATG5 and Beclin-1 enhanced resveratrol-induced caspase activation. Mechanistic analysis revealed that Beclin-1 did not interact with proapoptotic proteins Bax and Bak; however, Beclin-1 was found to interact with p53 in the cytosol and mitochondria upon resveratrol treatment. Importantly, resveratrol depleted ATPase 8 gene, and thus, reduced mitochondrial DNA (mtDNA) content, suggesting that resveratrol induces damage to mtDNA causing accumulation of dysfunctional mitochondria triggering autophagy induction. Together, our findings indicate that induction of autophagy during resveratrol-induced apoptosis is an adaptive response.     

Fine-scale population genetic structure of Endangered Caspian Sea trout,Salmo caspius: implications for conservation

Hydrobiologia - Many populations of Caspian Sea trout (Salmo caspius)—a nationally endangered species in Iran—have been extirpated or depleted due to anthropogenic impacts. The Lar...     

BMI1, Stem Cell Factor Acting as Novel Serum-biomarker for Caucasian and African-American Prostate Cancer

Background

Lack of reliable predictive biomarkers is a stumbling block in the management of prostate cancer (CaP). Prostate-specific antigen (PSA) widely used in clinics has several caveats as a CaP biomarker. African-American CaP patients have poor prognosis than Caucasians, and notably the serum-PSA does not perform well in this group. Further, some men with low serum-PSA remain unnoticed for CaP until they develop disease. Thus, there is a need to identify a reliable diagnostic and predictive biomarker of CaP. Here, we show that BMI1 stem-cell protein is secretory and could be explored for biomarker use in CaP patients.

Methodology/Principal Findings

Semi-quantitative analysis of BMI1 was performed in prostatic tissues of TRAMP (autochthonous transgenic mouse model), human CaP patients, and in cell-based models representing normal and different CaP phenotypes in African-American and Caucasian men, by employing immunohistochemistry, immunoblotting and Slot-blotting. Quantitative analysis of BMI1 and PSA were performed in blood and culture-media of siRNA-transfected and non-transfected cells by employing ELISA. BMI1 protein is (i) secreted by CaP cells, (ii) increased in the apical region of epithelial cells and stromal region in prostatic tumors, and (iii) detected in human blood. BMI1 is detectable in blood of CaP patients in an order of increasing tumor stage, exhibit a positive correlation with serum-PSA and importantly is detectable in patients which exhibit low serum-PSA. The clinical significance of BMI1 as a biomarker could be ascertained from observation that CaP cells secrete this protein in higher levels than cells representative of benign prostatic hyperplasia (BPH).

Conclusions/Significance

BMI1 could be developed as a dual bio-marker (serum and biopsy) for the diagnosis and prognosis of CaP in Caucasian and African-American men. Though compelling these data warrant further investigation in a cohort of African-American patients.     

Circulating myeloid-derived suppressor cells: An independent prognostic factor in patients with breast cancer

Evading immune destruction is a hallmark of cancer. Myeloid-derived suppressor cells (MDSCs), a heterogeneous population of myeloid immune cells, are thought to foster the establishment of an immunosuppressive tumor microenvironment, but it remains unclear how. This study aims to determine the levels of circulating MDSCs and their subpopulations and test their immunosuppressive functions in patients with breast cancer (BC). We analyzed the fractions of MDSCs in freshly isolated peripheral blood mononuclear cells of patients with BC and healthy donors using flow cytometry. Circulating MDSCs were further phenotyped using fluorescently labeled antihuman monoclonal antibodies. Coculture experiments revealed the effects of MDSCs on CD3⁺ T cell response. Moreover, we correlated circulating MDSC levels with clinicopathological features of patients with BC. We show that the fraction of HLA-DR ^– CD33 ⁺ MDSCs in peripheral blood is about 10-fold higher in patients with BC than in healthy control individuals. The levels of all MDSC subpopulations, including monocytic and granulocytic MDSCs, are significantly elevated. Coculture experiments of purified HLA-DR ^– CD33 ⁺ MDSCs and CD3 ⁺ T cells demonstrate that T cell proliferation is more effectively inhibited by BC patient-derived MDSCs than by healthy control MDSCs. Moreover, increased circulating MDSC levels robustly associate with advanced BC stage and positive lymph node status. By being more abundant and more effective T cell suppressors, BC patient-derived circulating MDSCs exert a dual immunosuppressive effect. Our findings pave the way to develop novel diagnostic and immunotherapeutic strategies, aimed at detecting and inhibiting MDSCs in patients with BC.     

The use of neamine as a molecular template: Identification of active site residues in the bacterial antibiotic resistance enzyme aminoglycoside 3′-phosphotransferase type IIa by mass spectroscopy

Four novel aminoglycoside-based affinity inactivators were shown to covalently modify the active site of aminoglycoside 3′-phosphotransferase type IIa (APH(3′)-IIa), an important resistance factor in bacteria for aminoglycoside antibiotics. Standard peptide mapping techniques failed with this enzyme. A novel mass spectroscopic analysis which combines protease digestion on the instrument probe, followed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is described which permitted rapid identification of the sites of protein modification. By this new technique, Glu-3 and Asp-23 were identified as active-site residues, the side chains of which potentially may serve as counter ions for the ammonium functionalities at positions 6′, and 1 and 3 of the antibiotic substrates, respectively. These findings contradict previous assertions that the C-terminal third of the enzyme should form the active site, by placing the active site clearly in the N-terminal portion of the enzyme.     

Cardiac-restricted angiotensin-converting enzyme overexpression causes conduction defects and connexin dysregulation

Renin-angiotensin (RAS) system activation is associated with an increased risk of sudden death. Previously, we used cardiac-restricted angiotensin-converting enzyme (ACE) overexpression to construct a mouse model of RAS activation. These ACE 8/8 mice die prematurely and abruptly. Here, we have investigated cardiac electrophysiological abnormalities that may contribute to early mortality in this model. In ACE 8/8 mice, surface ECG voltages are reduced. Intracardiac electrograms showed atrial and ventricular potential amplitudes of 11% and 24% compared with matched wild-type (WT) controls. The atrioventricular (AV), atrio-Hisian (AH), and Hisian-ventricular (HV) intervals were prolonged 2.8-, 2.6-, and 3.9-fold, respectively, in ACE 8/8 vs. WT mice. Various degrees of AV nodal block were present only in ACE 8/8 mice. Intracardiac electrophysiology studies demonstrated that WT and heterozygote (HZ) mice were noninducible, whereas 83% of ACE 8/8 mice demonstrated ventricular tachycardia with burst pacing. Atrial connexin 40 (Cx40) and connexin 43 (Cx43) protein levels, ventricular Cx43 protein level, atrial and ventricular Cx40 mRNA abundances, ventricular Cx43 mRNA abundance, and atrial and ventricular cardiac Na(+) channel (Scn5a) mRNA abundances were reduced in ACE 8/8 compared with WT mice. ACE 8/8 mice demonstrated ventricular Cx43 dephosphorylation. Atrial and ventricular L-type Ca(2+) channel, Kv4.2 K(+) channel alpha-subunit, and Cx45 mRNA abundances and the peak ventricular Na(+) current did not differ between the groups. In isolated heart preparations, a connexin blocker, 1-heptanol (0.5 mM), produced an electrophysiological phenotype similar to that seen in ACE 8/8 mice. Therefore, cardiac-specific ACE overexpression resulted in changes in connexins consistent with the phenotype of low-voltage electrical activity, conduction defects, and induced ventricular arrhythmia. These results may help explain the increased risk of arrhythmia in states of RAS activation such as heart failure.