For efficient clearance of Mycobacterium tuberculosis (Mtb), macrophages tilt towards M1 polarization leading to the activation of transcription factors associated with the production of antibacterial effector molecules such as nitric oxide (NO) and proinflammatory cytokines such as interleukin 1 β (IL-1β) and tumor necrosis factor α (TNF-α). At the same time, resolution of inflammation is associated with M2 polarization with increased production of arginase and cytokines such as IL-10. The transcriptional and post-transcriptional mechanisms that govern the balance between M1 and M2 polarization, and bacteria-containing processes such as autophagy and trafficking of Mtb to lysosomes, are incompletely understood. Here we report for the first time, that the transcription factor KLF4 is targeted by microRNA-26a (miR-26a). During Mtb infection, downregulation of miR-26a (observed both ex vivo and in vivo) facilitates upregulation of KLF4 which in turn favors increased arginase and decreased iNOS activity. We further demonstrate that KLF4 prevents trafficking of Mtb to lysosomes. The CREB-C/EBPβ signaling axis also favors M2 polarization. Downregulation of miR-26a and upregulation of C/ebpbeta were observed both in infected macrophages as well as in infected mice. Knockdown of C/ebpbeta repressed the expression of selected M2 markers such as Il10 and Irf4 in infected macrophages. The importance of these pathways is substantiated by observations that expression of miR-26a mimic or knockdown of Klf4 or Creb or C/ebpbeta, attenuated the survival of Mtb in macrophages. Taken together, our results attribute crucial roles for the miR-26a/KLF4 and CREB-C/EBPβsignaling pathways in regulating the survival of Mtb in macrophages. These studies expand our understanding of how Mtb hijacks host signaling pathways to survive in macrophages, and open up new exploratory avenues for host-targeted interventions.

Background:The spectrum of liver dysfunction in children with dengue infection is wide and has been associated with disease severity.Aims:This study was undertaken to estimate the range of hepatic involvement in dengue infection in children.Materials and Methods:This study assessed the biochemical and clinical profile of hepatic involvement by dengue virus in 120 children with serologically positive dengue fever (DF), aged 2 months to 14 years.Results:All cases were grouped into DF without warning signs (Group 1), DF with warning signs (Group 2) and severe dengue (Group 3) according to revised World Health Organization 2009 criteria. The spectrum of hepatic manifestations included hepatomegaly (80.8%), hepatic tenderness (46.3%), jaundice (60%), raised aspartate transaminase (AST), alanine transaminase (ALT) and prolonged prothrombin time (41.7%) and reduced serum albumin (56%).Conclusions:Hepatic dysfunction was observed more in Groups 2 and 3. There was 84.4% and 93.75% ALT and AST elevation respectively in Group 2 and 94.5% and 95.9% ALT and AST elevation respectively in Group 3 and fulminant hepatic failure was observed in Group 3. Therefore in a child with fever, jaundice, hepatomegaly and altered liver function tests, the diagnosis of dengue infection should be strongly considered in areas where dengue infection is endemic.

Long noncoding RNAs (lncRNAs) are noncoding transcripts longer than 200 nucleotides, which show evidence of pervasive transcription and participate in a plethora of cellular regulatory processes. Although several noncoding transcripts have been functionally annotated as lncRNAs within the genome, not all have been proven to fulfill the criteria for a functional regulator and further analyses have to be done in order to include them in a functional cohort. LncRNAs are being classified and reclassified in an ongoing annotation process, and the challenge is fraught with ambiguity, as newer evidences of their biogenesis and functional implication come into light. In our effort to understand the complexity of this still enigmatic biomolecule, we have developed a new database entitled “LncRBase” where we have classified and characterized lncRNAs in human and mouse. It is an extensive resource of human and mouse lncRNA transcripts belonging to fourteen distinct subtypes, with a total of 83,201 entries for mouse and 133,361 entries for human: among these, we have newly annotated 8,507 mouse and 14,813 human non coding RNA transcripts (from UCSC and H-InvDB 8.0) as lncRNAs. We have especially considered protein coding gene loci which act as hosts for non coding transcripts. LncRBase includes different lncRNA transcript variants of protein coding genes within LncRBase. LncRBase provides information about the genomic context of different lncRNA subtypes, their interaction with small non coding RNAs (ncRNAs) viz. piwi interacting RNAs (piRNAs) and microRNAs (miRNAs) and their mode of regulation, via association with diverse other genomic elements. Adequate knowledge about genomic origin and molecular features of lncRNAs is essential to understand their functional and behavioral complexities. Overall, LncRBase provides a thorough study on various aspects of lncRNA origin and function and a user-friendly interface to search for lncRNA information. LncRBase is available at http://bicresources.jcbose.ac.in/zhumur/lncrbase.

Resveratrol, a trans-stilbene polyphenolic compound and its synthetic analogs are widely used bioactive molecules due to their remarkable chemo-preventive potential. Here, we have identified a novel synthetic trans-stilbene compound, Z-DAN-11 ((Z)-3-(3, 4-dimethoxyphenyl)-2-(3, 4, 5-trimethoxyphenyl) acrylonitrile) which shows remarkable efficacy in blocking tumor growth and progression both in vitro and in vivo. Z-DAN-11 inhibits proliferation of cancer cells in vitro through microtubule depolymerization that induced G2/M arrest and consequently leads to apoptotic cell death. More importantly, Z-DAN-11 shows limited cytotoxicity to normal cells as compared to cancer cells. Quite interestingly, we have found that Z-DAN-11-mediated ROS production helps in dramatic alteration in the mitochondrial redox status which critically contributes to the apoptosis. Mechanistic studies reveal that Z-DAN-11 induces the expression of pro-apoptotic proteins and decreases anti-apoptotic protein expression that decisively helps in the activation of caspase 8, caspase 9, and caspase 3, leading to cleavage of PARP1 and cell death via intrinsic and extrinsic pathways of apoptosis. Moreover, Z-DAN-11-mediated apoptosis of cancer cells is through a partial p53-dependent pathway, since both HCT116 p53−/− cells as well as p53-silenced cells (siRNA) were able to block apoptosis partially but significantly. Importantly, Z-DAN-11 also imparts its anti-tumorigenic effect by inhibiting clonogenic property and anchorage-independent growth potential of cancer cells at concentrations at least 10 times lower than that required for inducing apoptosis. Finally, in vivo study with immuno-competent syngeneic mice shows Z-DAN-11 to be able to impede tumor progression without any adverse side-effects. Hence, we identified a novel, synthetic trans-stilbene derivative with anti-tumorigenic potential which might tremendously help in devising potential therapeutic strategy against cancer.

Despite the high cure rates in childhood acute lymphoblastic leukemia (ALL), relapsed ALL remains a significant clinical problem. Genetic heterogeneity does not adequately explain variations in response to therapy. The chemoprotective tumor microenvironment may additionally contribute to disease recurrence. This study identifies metabolic reprogramming of leukemic cells by bone marrow stromal cells (BMSC) as a putative mechanism of drug resistance. In a BMSC-extracellular matrix culture model, BMSC produced chemoprotective soluble factors and facilitated the emergence of a reversible multidrug resistant phenotype in ALL cells. BMSC environment induced a mitochondrial calcium influx leading to increased reactive oxygen species (ROS) levels in ALL cells. In response to this oxidative stress, drug resistant cells underwent a redox adaptation process, characterized by a decrease in ROS levels and mitochondrial membrane potential with an upregulation of antioxidant production and MCL-1 expression. Similar expanded subpopulations of low ROS expressing and drug resistant cells were identified in pre-treatment bone marrow samples from ALL patients with slower response to therapy. This suggests that the bone marrow microenvironment induces a redox adaptation in ALL subclones that protects against cytotoxic stress and potentially gives rise to minimal residual disease. Targeting metabolic remodeling by inhibiting antioxidant production and antiapoptosis was able to overcome drug resistance. Thus metabolic plasticity in leukemic cell response to environmental factors contributes to chemoresistance and disease recurrence. Adjunctive strategies targeting such processes have the potential to overcome therapeutic failure in ALL.