Transcription factors and DNA/histone modification enzymes work in concert to establish and maintain cell identity. CD4⁺ and CD8⁺ T cells are key players in cellular immunity with distinct functions. Recent studies offer novel insights into how their identities are established in the thymus and maintained in the periphery during immune responses. During thymic maturation, Thpok, HDAC1 and HDAC2 guard CD4⁺ T cells from activation of CD8⁺ cytotoxic genes, and Tcf1 and Lef1 utilize their intrinsic HDAC activity to shut down CD4⁺ lineage-associated genes in CD8⁺ T cells. In activated CD4⁺ T cells, Tcf1 and Lef1 act upstream of the Bcl6-Blimp1 axis to direct differentiation of follicular helper T (Tfh) cells, and prevent diversion of Tfh to IL-17-producing cells. In parallel, T-bet, together with Eomes or Blimp1, ensures proper induction of the cytotoxic program in CD8⁺ effectors elicited by acute infection, and prevents generation of pathogenic, IL-17-producing CD8⁺ effector T cells. Antigen persistence due to chronic viral infection leads to CD8⁺ T cell exhaustion. A portion of exhausted CD8⁺ T cells has the capacity to activate the Tfh program in a Tcf1-dependent manner. Those Tfh-like CD8⁺ T cells exhibit enhanced proliferative capacity in response to PD-1 blockage therapy and are more effective in curtailing viral replication. Thus, dissecting the molecular aspects of T cell identity, during development and immune responses, may lead to new therapies for treating autoimmunity, tumors, and persistent infections.

BACKGROUND: Organoid is an in vitro three-dimensional organ-bud that shows realistic microanatomy and physiological relevance. The progress in generating organoids that faithfully recapitulate humanin vivo tissue composition has extended organoid applications from being just a basic research tool to a translational platform with a wide range of uses. Study of host-microbial interactions relies on model systems to mimic thein vivo infection. Researchers have developed various experimental models in vitro and in vivo to examine the dynamic host-microbial interactions. For some infectious pathogens, model systems are lacking whereas some of the used systems are far from optimal.

OBJECTIVE: In the present work, we will review the brief history and recent findings using organoids for studying host-microbial interactions.

METHODS: A systematic literature search was performed using the PubMed search engine. We also shared our data and research contribution to the field.

RESULTS: we summarize the brief history of 3D organoids. We discuss the feasibility of using organoids in studying host-microbial interactions, focusing on the development of intestinal organoids and gastric organoids. We highlight the advantage and challenges of the new experimental models. Further, we discuss the future direction in using organoids in studying host-microbial interactions and its potential application in biomedical studies.

CONCLUSION: In combination with genetic, transcriptome and proteomic profiling, both murine- and human-derived organoids have revealed crucial aspects of development, homeostasis and diseases. Specifically, human organoids from susceptible host will be used to test their responses to pathogens, probiotics, and drugs. Organoid system is an exciting tool for studying infectious disease, microbiome, and therapy.

BACKGROUND: Erythropoiesis is regulated by a range of intrinsic and extrinsic factors, including different cytokines. Recently, the role of catecholamines has been highlighted in the development of erythroid cell lineages.

OBJECTIVE: This study focuses on the biological links interconnecting erythroid development and the sympathetic nervous system. The emerging evidence that underscores the role of catecholamines in the regulation of erythropoietin and other erythropoiesis cytokines are thoroughly reviewed, in addition to elements such as iron and the leptin hormone that are involved in erythropoiesis.

METHODS: Relevant English-language studies were identified and retrieved from the PubMed search engine (1981–2017) using the following keywords: “Erythropoiesis”, “Catecholamines”, “Nervous system”, and “Cytokines.”

RESULTS: Chronic social stress alters and suppresses erythroid development. However, the physiological release of catecholamines is an additional stimulator of erythropoiesis in the setting of anemia. Therefore, the severity and timing of catecholamine secretion might distinctly regulate erythroid homeostasis.

CONCLUSION: Understanding the relationship of catecholamines with different elements of the erythroid islands will be essential to find the tightly regulated production of red blood cells (RBCs) in both chronic and physiological catecholamine activation.

BACKGROUND: Periodontitis i.e. inflammation of the periodontium is a multifactorial disease. Antimicrobial peptides (AMPs) which demonstrate a broad-spectrum of activity against varied number of bacteria, fungi, viruses, and parasites, and cancerous cells have been linked to periodontitis. The AMPs even possess the caliber of immunomodulation, and are significantly responsive to innate immuno-stimulation and infections. LL-37 plays a salubrious role by preventing and in treatment of chronic forms of periodontitis.

OBJECTIVE: In the present work we will review the role of antimicrobial peptide LL-37 in periodontitis.

METHODS: A systematic search was carried out from the beginning till August, 2016 using the Pubmed search engine. The keywords included “LL-37,” “periodontitis,” “Papillon–Lefevre syndrome,” “Morbus Kostmann,” “Haim-Munk syndrome” along with use of Boolean operator “and.”

RESULTS: The search resulted in identifying 67 articles which included articles linking LL-37 with periodontitis, articles on Papillon–Lefevre syndrome, Morbus Kostmann, Haim-Munk syndrome, LL-37 and periodontitis and articles on pathogenicity of periodontitis.

CONCLUSION: The literature search concluded that LL-37 plays a pivotal role in preventing and treatment of severe form of periodontitis.

BACKGROUND: Neuronal primary cilia are sensory organelles that are critically involved in the proper growth, development, and function of the central nervous system (CNS). Recent work also suggests that they signal in the context of CNS injury, and that abnormal ciliary signaling may be implicated in neurological diseases.

METHODS: We quantified the distribution of neuronal primary cilia alignment throughout the normal adult mouse brain by immunohistochemical staining for the primary cilia marker adenylyl cyclase III (ACIII) and measuring the angles of primary cilia with respect to global and local coordinate planes. We then introduced two different models of acute brain insult—temporal lobe seizure and cerebral ischemia, and re-examined neuronal primary cilia distribution, as well as ciliary lengths and the proportion of neurons harboring cilia.

RESULTS: Under basal conditions, cortical cilia align themselves radially with respect to the cortical surface, while cilia in the dentate gyrus align themselves radially with respect to the granule cell layer. Cilia of neurons in the striatum and thalamus, by contrast, exhibit a wide distribution of ciliary arrangements. In both cases of acute brain insult, primary cilia alignment was significantly disrupted in a region-specific manner, with areas affected by the insult preferentially disrupted. Further, the two models promoted differential effects on ciliary lengths, while only the ischemia model decreased the proportion of ciliated cells.

CONCLUSIONS:These findings provide evidence for the regional anatomical organization of neuronal primary cilia in the adult brain and suggest that various brain insults may disrupt this organization.

BACKGROUND: Metabolic networks are complex and system of highly connected chemical reactions and hence it needs a system level computational approach to identify the genotype- phenotype relationship. The study of essential genes and reactions and synthetic lethality of genes and reactions plays a crucial role in explaining functional links between genes and gene function predictions.

METHODS: Flux balance analysis (FBA) has been developed as a powerful method for the in silico analyses of metabolic networks. In this study, we present the comparative analysis of the genomic scale metabolic networks of the four microorganisms i.e.Salmonella typhimurium, Mycobacterium tuberculosis, Staphylococcus aureus,andHelicobacter pylori. The fluxes of all reaction were obtained and the growth rate of the organism was calculated by setting the biomass reaction as the objective function.

RESULTS & CONCLUSIONS:The average lethality fraction of all the four organisms studied ranged from 0.2 to 0.6. It was also observed that there are very few metabolites which are highly connected. Those metabolites that are highly connected are supposed to be the ‘global players’ similar to the hub protein in the protein – protein interaction network.

BACKGROUND: The microbes living in planta termed ‘endophytes’ is bestowed with the potential to produce bioactive substances. The aim of this investigation was focused on the isolation and molecular identification of the fungal endophytes fromZingiber nimmonii (J. Graham) Dalzell., an endemic medicinal plant species of the ‘Western ghats’, a hotspot location in southern India and characterization of the secondary metabolites responsible for the antioxidant and DNA protective capacity using chromatography and mass spectrometry techniques.

METHODS: Endophytic fungi were isolated and identified by sequencing the Internal Transcribed Spacer (ITS). The secondary metabolites were extracted with ethyl acetate and evaluated for the total phenolic, flavonoid and antioxidant capacities. The isolates with potential antioxidative property were further analyzed for the DNA protection ability and the presence of bioactive phenolic compounds by High Performance Liquid Chromatography (HPLC) and Electrospray Ionization-Mass Spectroscopy/Mass Spectroscopy (ESI-MS/MS) techniques.

RESULTS: Endophytic fungi belonging to 11 different taxa were identified. The total phenolic content of the extracts ranged from 10.8±0.7 to 81.6±6.0 mg gallic acid equivalent/g dry extract. Flavonoid was present in eight extracts in the range of 5.2±0.5 to 24.3±0.9 mg catechin equivalents/g dry extract.Bipolaris specifera, Alternaria tenuissima, Aspergillus terreus, Nectria haematococca and Fusarium chlamydosporum extracts exhibited a potentially high antioxidant capacity. Characterization of the extracts revealed an array of phenolic acids and flavonoids.N. haematococcaand F. chlamydosporum extracts contained quercetin and showed DNA protection ability.

CONCLUSION: This study is the first comprehensive report on the fungal endophytes from Z. nimmonii, as potential sources of antioxidative and DNA protective compounds. The study indicates that Z. nimmonii endophytes are potential sources of antioxidants over the plant itself.