Evaluation of cell-free seminal mRNA for the diagnosis of obstruction as the cause of azoospermia in infertile men: A prospective cohort study.

Differentiating obstructive (OA) from non-obstructive (NOA) azoospermia is clinically important in managing infertile men. Classically, the differentiation has been based on clinical, hormonal and histological analysis. Histological tests are invasive and may miss spermatogenic areas. Seminal fluid can serve as a medium to assess the status of spermatogenesis and presence or absence of certain markers can help diagnosing and differentiating azoospermia. We evaluated the role of cell-free seminal markers: DDX4, PRM1 and PRM2 in diagnosing and differentiating between OA and NOA and classifying their subtypes. We observed DDX4 was more sensitive for NOA compared with OA. Among various subtypes of NOA, DDX4 positivity was higher in patients with maturation arrest and hypospermatogenesis compared with Sertoli cell only syndrome. PRM1 and PRM2 had very low positivity rate for any meaningful comparison. Seminal cell-free markers can serve as non-invasive tests in diagnosing and differentiating etiologies of azoospermia but their validity needs to be proved in long-term trials with more refined molecular techniques.

Engulfment of Hb-activated platelets differentiates monocytes into pro-inflammatory macrophages in PNH patients.

The distinct response shown by different phenotypes of macrophages and monocytes under various clinical conditions has put the heterogeneity of these cells into focus of investigation for several diseases. Recently, we have described that after engulfing hemoglobin (Hb)-activated platelets, classical monocytes differentiated into pro-inflammatory phenotypes, which were abundant in the circulation of paroxysmal nocturnal hemoglobinuria (PNH) and sickle cell disease patients. Our current study shows that upon engulfment of Hb-activated platelets, monocytes differentiate into M1-macrophages under M1-polarization stimulus (GM-CSF, IFN-γ + LPS). When grown under M2-polarization stimulus (M-CSF, IL-4 + IL13), the cells exhibited an M1-like phenotype, secreted elevated levels of pro-inflammatory cytokines including TNF-α and IL-1ß, and displayed loss of the secretion of cytokine such as IL-10 and also phagocytic ability unlike the conventional M2 macrophages. Interestingly, when differentiated under the above polarization stimulus, monocytes from PNH patients expressed high levels of CD80 and phospho-STAT1, like M1 macrophages. Hemolytic mice also exhibited a gradual increase in monocyte-platelet aggregates in circulation and accumulation of CD80high macrophages in thioglycollate-induced inflamed peritoneum. The spleen of the mice was also populated by CD80high macrophages with compromised phagocytic capacity. Our findings suggest that the hemolytic environment and specifically the Hb-activated platelets, which are abundant in circulation during intravascular hemolysis, closely regulate monocyte differentiation.

MRN complex-dependent recruitment of ubiquitylated BLM helicase to DSBs negatively regulates DNA repair pathways.

Mutations in BLM in Bloom Syndrome patients predispose them to multiple types of cancers. Here we report that BLM is recruited in a biphasic manner to annotated DSBs. BLM recruitment is dependent on the presence of NBS1, MRE11 and ATM. While ATM activity is essential for BLM recruitment in early phase, it is dispensable in late phase when MRE11 exonuclease activity and RNF8-mediated ubiquitylation of BLM are the key determinants. Interaction between polyubiquitylated BLM and NBS1 is essential for the helicase to be retained at the DSBs. The helicase activity of BLM is required for the recruitment of HR and c-NHEJ factors onto the chromatin in S- and G1-phase, respectively. During the repair phase, BLM inhibits HR in S-phase and c-NHEJ in G1-phase. Consequently, inhibition of helicase activity of BLM enhances the rate of DNA alterations. Thus BLM utilizes its pro- and anti-repair functions to maintain genome stability.

Platelet activation determines the severity of thrombocytopenia in dengue infection.

Thrombocytopenia is common in patients with dengue virus (DENV) infections. With a focus on understanding the possible mechanism of thrombocytopenia in DENV infections we described a direct correlation between activation and depletion of platelets in patients. Our data showed a sharp decrease in platelet counts at day 4 of fever in patients. The high DENV genome copies in platelets correlated directly with the elevated platelet activation along with increased binding of complement factor C3 and IgG on their surface at day 4. Recovery in platelet count was observed on day 10 through day 6 and 8 with simultaneous decrease in platelet activation markers. Further, our in vitro data supported the above observations describing a concentration-dependent increase in platelet activation by DENV serotype-2. The high copy number of DENV2 genome in the platelet pellet correlated directly with platelet activation, microparticle generation and clot formation. Furthermore the DENV2-activated platelets were phagocytosed in large numbers by the monocytes. The DENV2-mediated lysis and clearance of platelets were abrogated in presence of platelet activation inhibitor, prostacyclin. These observations collectively suggest that platelet activation status is an important determinant of thrombocytopenia in dengue infections. A careful strategy of inactivation of platelets may rescue them from rapid destruction during DENV infections.

HbS Binding to GP1bα Activates Platelets in Sickle Cell Disease.

Intravascular hemolysis increases the risk of thrombosis in hemolytic disorders. Our previous study showed that the binding of adult hemoglobin (HbA) to glycoprotein (GP) 1bα induced the activation of platelets. The elevated plasma Hb or platelet surface bound Hb positively correlated with platelet activation in patients with paroxysmal nocturnal hemoglobinuria (PNH). Furthermore, this study shows that the sickle Hb [HbS, occurs due to single nucleotide polymorphism at A>T of ß-globin gene of Hb and causes sickle cell disease (SCD)] also bound to GP1bα and activated platelets in a concentration-dependent manner. The HbS bound to glycocalicin (extramembranous part of GP1bα) with KD ~ 10.46 ± 3 µM. HbS induced phosphorylation of signaling adapter proteins, such as Lyn, PI3K, Akt and ERK in platelets, and also increased the surface expression of platelet activation markers such as P-selectin (10.7 fold) and PAC1 binding (10.4 fold) in platelet surface in a concentration-dependent manner. HbS also increased the platelet microparticle-generation (4.7 fold) and thrombus-formation (4.3 fold) in a concentration-dependent manner. An elevated level of extracellular Hb in plasma correlated directly with platelet activation markers such as P-selectin (r = 0.7947), PAC1 binding (r = 0.5914) on platelet surface and plasma levels of platelet-derived microparticles (r = 0.7834) in patients with SCD. Our study therefore suggests that the HbS-induced platelet activation may play a crucial role in intravascular clot formation observed in SCD patients characterized by high propensity to vascular occlusion and hypercoagulable states.

Sin3: insight into its transcription regulatory functions.

Sin3, a large acidic protein, shares structural similarity with the helix-loop-helix dimerization domain of proteins of the Myc family of transcription factors. Sin3/HDAC corepressor complex functions in transcriptional regulation of several genes and is therefore implicated in the regulation of key biological processes. Knockdown studies have confirmed the role of Sin3 in cellular proliferation, differentiation, apoptosis and cell cycle regulation, emphasizing Sin3 as an essential regulator of critical cellular events in normal and pathological processes. The present review covers the diverse functions of this master transcriptional regulator as well as illustrates the redundant and distinct functions of its two mammalian isoforms.