Rapid re-organization of the actin cytoskeleton supports T-cell trafficking towards immune sites and interaction with antigen presenting cells (APCs). F-actin rearrangement enables T-cell trafficking ...by stabilizing adhesion to vascular endothelial cells and promoting transendothelial migration. T-cell/APC immune synapse (IS) maturation also relies upon f-actin-anchored LFA-1:ICAM-1 ligation. Therefore, efficient T-cell responses require tight regulation of f-actin dynamics. In this review, we summarize how the actin-bundling protein L-plastin (LPL) regulates T-cell activation and migration. LPL enhances f-actin polymerization and also directly binds to the β2 chain of the integrin LFA-1 to support intercellular adhesion and IS formation in human and murine T cells. LPL- deficient T cells migrate slowly in response to chemo-attractants such as CXCL12, CCL19, and poorly polarize towards ICAM-1. Loss of LPL impairs thymic egress and intranodal motility. LPL is also required for T-cell IS maturation with APCs, and therefore for efficient cytokine production and proliferation. LPL
-/-
mice are less susceptible to T-cell mediated pathologies, such as allograft rejection and experimental autoimmune encephalomyelitis (EAE). LPL activity is regulated by its N-terminal “headpiece”, which contains serine and threonine phosphorylation and calcium- and calmodulin-binding sites. LPL phosphorylation is required for lamellipodia formation during adhesion and migration, and also for LFA-1 clustering during IS formation. However, the precise molecular interactions by which LPL supports T-cell functional responses remain unclear. Future studies elucidating LPL-mediated regulation of T-cell migration and/or activation may illuminate pathways for therapeutic targeting in T-cell-mediated diseases.
This report describes simple syntheses of a new class of palladium(II) pincer complexes having NNN and CNN coordination modes. The new complexes were fully characterized with the help of 1H and ...13C{1H} NMR, HRMS, and IR spectroscopy. The structure and bonding modes of complexes were further authenticated with the help of single-crystal X-ray diffraction. Thermally robust and moisture-/air-insensitive palladium pincer complexes C1–C4 have been used as catalysts for cross dehydrogenative coupling (CDC) reactions of two heteroarenes and found to be very efficient. The catalyst was successful in activating the C–H bond of a variety of heteroarenes, including benzimidazole, imidazole, benzothiazole, imidazopyridine, thiophene, and furan, with only 1.0 mol % of catalyst, achieving excellent yields of the coupled products. The catalyst showed excellent tolerance toward functional groups such as CHO, COMe, COOMe, COOEt, CONHPh, Me, CN, Br, and Cl. Further, the catalyst is reusable up to four reaction cycles with only a minor loss in its efficiency. The mechanism of the CDC reaction was investigated through control experiments, and it has been suggested that a palladium acetate analogue of the NNN pincer ligand (C5) is the active catalyst.
Adaptive changes to oxygen availability are critical for cell survival and tissue homeostasis. Prolonged oxygen deprivation due to reduced blood flow to cardiac or peripheral tissues can lead to ...myocardial infarction and peripheral vascular disease, respectively. Mammalian cells respond to hypoxia by modulating oxygen-sensing transducers that stabilize the transcription factor hypoxia-inducible factor 1α (HIF-1α), which transactivates genes governing angiogenesis and metabolic pathways. Oxygen-dependent changes in HIF-1α levels are regulated by proline hydroxylation and proteasomal degradation. Here we provide evidence for what we believe is a novel mechanism regulating HIF-1α levels in isolated human ECs during hypoxia. Hypoxia differentially increased microRNA-424 (miR-424) levels in ECs. miR-424 targeted cullin 2 (CUL2), a scaffolding protein critical to the assembly of the ubiquitin ligase system, thereby stabilizing HIF-α isoforms. Hypoxia-induced miR-424 was regulated by PU.1-dependent transactivation. PU.1 levels were increased in hypoxic endothelium by RUNX-1 and C/EBPα. Furthermore, miR-424 promoted angiogenesis in vitro and in mice, which was blocked by a specific morpholino. The rodent homolog of human miR-424, mu-miR-322, was significantly upregulated in parallel with HIF-1α in experimental models of ischemia. These results suggest that miR-322/424 plays an important physiological role in post-ischemic vascular remodeling and angiogenesis.
The establishment of persistent infections and the reactivation of persistent bacteria to active bacilli are the two hurdles in effective tuberculosis treatment. Mycobacterium tuberculosis, an ...etiologic tuberculosis agent, adapts to numerous antibiotics and resists the host immune system causing a disease of public health concern. Extensive research has been employed to combat this disease due to its sheer ability to persist in the host system, undetected, waiting for the opportunity to declare itself. Persisters are a bacterial subpopulation that possesses transient tolerance to high doses of antibiotics. There are certain inherent mechanisms that facilitate the persister cell formation in Mycobacterium tuberculosis, some of those had been characterized in the past namely, stringent response, transcriptional regulators, energy production pathways, lipid metabolism, cell wall remodeling enzymes, phosphate metabolism, and proteasome protein degradation. This article reviews the recent advancements made in various in vitro persistence models that assist to unravel the mechanisms involved in the persister cell formation and to hunt for the possible preventive or treatment measures. To tackle the persister population the immunodominant proteins that express specifically at the latent phase of infection can be used for diagnosis to distinguish between the active and latent tuberculosis, as well as to select potential drug or vaccine candidates. In addition, we discuss the genes engaged in the persistence to get more insights into resuscitation and persister cell formation. The in-depth understanding of persistent cells of mycobacteria can certainly unravel novel ways to target the pathogen and tackle its persistence.
Hypoxia-driven changes in the tumor microenvironment facilitate cancer metastasis. In the present study, we investigated the regulatory cross talk between endocytic pathway, hypoxia, and tumor ...metastasis. Dynamin 2 (DNM2), a GTPase, is a critical mediator of endocytosis. Hypoxia decreased the levels of DNM2. DNM2 promoter has multiple hypoxia-inducible factor (HIF)-binding sites and genetic deletion of them relieved hypoxia-induced transcriptional suppression. Interestingly, DNM2 reciprocally regulated HIF. Inhibition of DNM2 GTPase activity and dominant-negative mutant of DNM2 showed a functional role for DNM2 in regulating HIF. Furthermore, the opposite strand of DNM2 gene encodes miR-199a, which is similarly reduced in cancer cells under hypoxia. miR-199a targets the 3′-UTR of HIF-1α and HIF-2α. Decreased miR-199a expression in hypoxia increased HIF levels. Exogenous expression of miR-199a decreased HIF, cell migration, and metastasis of ovarian cancer cells. miR-199a–mediated changes in HIF levels affected expression of the matrix-remodeling enzyme, lysyloxidase (LOX). LOX levels negatively correlated with progression-free survival in ovarian cancer patients. These results demonstrate a regulatory relationship between DNM2, miR-199a, and HIF, with implications in cancer metastasis.
Supply chain resilience is widely receiving attention during the past decade. Collaboration and visibility enhancement in supply chains is a key to achieve resilience and robustness in supply chains. ...Collaborative Planning, Forecasting and Replenishment (CPFR) is always been one of the difficult, yet powerful tool for collaboration in supply chains. Companies, in general attempt to address the technological side of changes, but avoid addressing the non-technological side of it, while implementing CPFR. This paper aims to explore the technological and non-technological enablers of CPFR, separately considering the Indian manufacturing industries and study their causal relations, using the Interpretive Structural Modeling (ISM). The results are beneficial, as managers can concentrate on causal enablers, while implementing CPFR. The success factors for implementation can slightly vary across different industries, but the applicability of the result is wider due to several common issues that arise during its implementation. Thus, the paper aims to provide directions for considering the most influencing enablers that can act as critical factors in the successful implementation of the CPFR. These influential enablers can be given much focus to reduce the vulnerabilities and to enhance the resilience capabilities of firms and their supply chains.
The prevalence of bacterial persisters is related to their phenotypic diversity and is responsible for the relapse of chronic infections. Tolerance to antibiotic therapy is the hallmark of bacterial ...persistence. In this study, we have screened a transposon library of
mc
155 strain using antibiotic tolerance, survival in mouse macrophages, and biofilm-forming ability of the mutants. Out of 10 thousand clones screened, we selected ten mutants defective in all the three phenotypes. Six mutants showed significantly lower persister abundance under different stress conditions. Insertions in three genes belonging to the pathways of oxidative phosphorylation
(
), biotin metabolism
(
), and oxidative metabolism
, a flavoprotein monooxygenase, significantly reduced the number of live cells, suggesting their role in pathways promoting long-term survival. Another group that displayed a moderate reduction in CFU included a glycosyltransferase,
, a hydrogenase subunit,
(
), and a DNA binding protein,
. The study has revealed potential candidates likely to facilitate the long-term survival of
. The findings offer new targets to develop antibiotics against persisters. Further, investigating the corresponding genes in
may provide valuable leads in improving the treatment of chronic and persistent tuberculosis infections.
Flavopiridol is a flavone synthesized from the natural product rohitukine, which is derived from an Indian medicinal plant, namely Dysoxylum binectariferum Hiern. A deeper understanding of the ...biological mechanisms by which such molecules act may allow scientists to develop effective therapeutic strategies against a variety of life-threatening diseases, such as cancer, viruses, fungal infections, parasites, and neurodegenerative diseases. Mechanistic insight of flavopiridol reveals its potential for kinase inhibitory activity of CDKs (cyclin-dependent kinases) and other kinases, leading to the inhibition of various processes, including cell cycle progression, apoptosis, tumor proliferation, angiogenesis, tumor metastasis, and the inflammation process. The synthetic derivatives of flavopiridol have overcome a few demerits of its parent compound. Moreover, these derivatives have much improved CDK-inhibitory activity and therapeutic abilities for treating severe human diseases. It appears that flavopiridol has potential as a candidate for the formulation of an integrated strategy to combat and alleviate human diseases. This review article aims to unravel the potential therapeutic effectiveness of flavopiridol and its possible mechanism of action.
CXXC5 is a member of the CXXC‐type zinc finger epigenetic regulators. Various hematopoietic and nonhematopoietic roles have been assigned to CXXC5. In the present study, the role of Cxxc5 in ...myelopoiesis was studied using overexpression and short hairpin RNA‐mediated knockdown in mouse early stem and progenitor cells defined as Lineage− Sca‐1+c‐Kit+ (LSK) cells. Knockdown of Cxxc5 in mouse progenitor cells reduced monocyte and increased granulocyte development in ex vivo culture systems. In addition, ex vivo differentiation and proliferation experiments demonstrated that the expression of Cxxc5 affects the cell cycle in stem/progenitor cells and myeloid cells. Flow cytometry‐based analyses revealed that down‐regulation of Cxxc5 leads to an increase in the percentage of cells in the S phase, whereas overexpression results in a decrease in the percentage of cells in the S phase. Progenitor cells proliferate more after Cxxc5 knockdown, and RNA sequencing of LSK cells, and single‐cell RNA sequencing of differentiating myeloid cells showed up‐regulation of genes involved in the regulation of cell cycle after Cxxc5 knockdown. These results provide novel insights into the physiologic function of Cxxc5 during hematopoiesis, and demonstrate for the first time that it plays a role in monocyte development.
Cxxc5 is expressed in mouse hematopoietic stem/progenitor cells and its expression affects cell cycle, and differentiation of monocytes during myelopoiesis.
Schiff base ligands (L1: sulfated and L2: selenated) having a ferrocene core synthesized by reacting ferrocene-carboxaldehyde with 2-(phenylthio/seleno)ethylamine on treatment with Na
PdCl
in the ...presence of NaOAc give cyclopalladated complexes Pd(L1/L2-H)Cl (1/2). Complex 1 of a sulfated Schiff base L1, on reacting with one equivalent of triphenylphosphine gives complex Pd(L1-H)PPh
Cl (3), formed due to cleavage of a Pd-S bond. With 2 such a reaction does not occur, as a Pd-Se bond being stronger than that of its sulfur analogue does not get cleaved. L1, L2 and their complexes 1-3 were authenticated with HR-MS,
H,
C{
H} and
Se{
H} NMR spectroscopy. The single crystal structures of 1-3 were determined with X-ray diffraction. Palladium in all three complexes has nearly a square planar geometry. The Pd-S, Pd-Se and Pd-P bond distances are 2.4249(12), 2.5058(14) and 2.2445(17) Å respectively. The catalytic activity of complexes 1-3 was explored for O-arylation of phenol and Suzuki-Miyaura coupling (SMC) of phenylboronic acid with aryl bromides and chlorides. The optimum reaction time for SMC of ArBr is 3 h whereas for ArCl it is 6 h. The TON values of O-arylation catalyzed with complexes 1-3 are up to ∼170 (TOF, 28 h
) and SMC ∼9300 (TOF, 3100 h
) for the reaction time of the order of 3 and 6 h respectively. The catalytic process is somewhat more efficient with 2 (Pd bonded with a selenoether group), than 3, followed by 1.
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