Transcriptional elongation control of hypoxic response.

The release of paused RNA polymerase II (RNAPII) from promoter-proximal regions is tightly controlled to ensure proper regulation of gene expression. The elongation factor PTEF-b is known to release paused RNAPII via phosphorylation of the RNAPII C-terminal domain by its cyclin-dependent kinase component, CDK9. However, the signal and stress-specific roles of the various RNAPII-associated macromolecular complexes containing PTEF-b/CDK9 are not yet clear. Here, we identify and characterize the CDK9 complex required for transcriptional response to hypoxia. Contrary to previous reports, our data indicate that a CDK9 complex containing BRD4 but not AFF1/4 is essential for this hypoxic stress response. We demonstrate that BRD4 bromodomains (BET) are dispensable for the release of paused RNAPII at hypoxia-activated genes and that BET inhibition by JQ1 is insufficient to impair hypoxic gene response. Mechanistically, we demonstrate that the C-terminal region of BRD4 is required for Polymerase-Associated Factor-1 Complex (PAF1C) recruitment to establish an elongation-competent RNAPII complex at hypoxia-responsive genes. PAF1C disruption using a small-molecule inhibitor (iPAF1C) impairs hypoxia-induced, BRD4-mediated RNAPII release. Together, our results provide insight into potentially targetable mechanisms that control the hypoxia-responsive transcriptional elongation.

Potent MOR Agonists from 2'-Hydroxy-5,9-dimethyl-N-phenethyl Substituted-6,7-benzomorphans and from C8-Hydroxy, Methylene and Methyl Derivatives of N-Phenethylnormetazocine.

(-)-5,9-Dimethyl-6,7-benzomorphan (normetazocine) derivatives with a para-OH or ortho-F substituent in the aromatic ring of the N-phenethyl moiety were synthesized and found to have subnanomolar potency at MOR, and both were fully efficacious in vitro. These new compounds, (1R,5R,9R)-6,11-dimethyl-3-(2-fluorophenethyl)-1,2,3,4,5,6-hexahydro-2,6-methanobenzo[d]azocin-8-ol and (1R,5R,9R)-6,11-dimethyl-3-(4-hydroxyphenethyl)-1,2,3,4,5,6-hexahydro-2,6-methanobenzo[d]azocin-8-ol, were more potent than the unsubstituted compound N-phenethylnormetazocine and about 30 or 40 times more potent than morphine, respectively. A variety of substituents in the ortho, meta, or para position in the aromatic ring of the N-phenethyl moiety were synthesized, 25 of these compounds, and found to have varying effects on potency and efficacy as determined by the forskolin-induced cAMP accumulation assay. The N-phenethyl moiety was also modified by increasing chain length to form a N-phenylpropyl side chain with and without a para-nitro moiety, and by an N-cinnamyl side chain. Also, an indole ethylamine normetazocine was synthesized to replace the N-phenethylamine side chain in normetazocine. The phenylpropylamine, propenylamine (cinnamyl) and the para-nitropropylamine had little or no MOR potency. The indole-ethylamine on the normetazocine nucleus, however, had moderate potency (MOR EC50 = 12 nM), and was fully efficacious (%Emax = 102%) in the cAMP assay. Retention of the N-phenethyl moiety and the addition of alkyl and alkenyl moieties on C8 in (-)-N-phenethylnormetazocine gave a C8-methylene derivative that had subnanomolar potency at MOR and a C8-methyl analog that had nanomolar potency. Five C8-substituted compounds were synthesized.

Secretome of Young Mesenchymal Stromal Cells Rejuvenates Aged Mesenchymal Stromal Cells by Normalizing Their Phenotype and Restoring Their Differentiation Profile.

During aging, the proliferation and differentiation ability of mesenchymal stem/stromal cells (MSCs) gets affected, and hence, aged MSCs are not preferred for regenerative purposes. Rapid identification of aging-associated changes within MSCs and the mechanistic pathways involved are necessary to determine optimal cell sources to treat musculoskeletal disorders in older patients. In the present study, we have identified a set of phenotypic markers, namely downregulated expression of CD90 and upregulated expression of CD45, as age-defining markers for the bone marrow-derived MSCs. We also show that these phenotypic changes in aged MSCs correlate with their aging-mediated differentiation defects. We find that oxidative stress signaling leading to the activation of nuclear factor kappa B (NF-κB) plays an essential role in altering the phenotype and differentiation ability of the aged MSCs. We further show that treatment of aged MSCs with the conditioned medium (CM) derived from young MSCs (young-CM) restored their phenotype and differentiation potential to the young-like by ameliorating activation of NF-κB signaling in them. Similar changes could also be achieved by using an inhibitor of NF-κB signaling, showing that oxidative stress-induced NF-κB activation is the causative factor in the aging of MSCs. Additionally, we show that treating young MSCs with hydrogen peroxide mimics all the aging-mediated changes in them, underscoring the involvement of oxidative stress in the aging of MSCs. Overall, our data suggest that the altered expression of CD90 and CD45 surface markers can be used as a primary screen to identify the onset of aging in the MSCs, which can be quickly reversed by their in vitro treatment with young-CM or NF-κB inhibitor. Our study also puts the phenotypic characterization of MSCs in a clinical perspective.

Its all in the name: Another new Cyrtodactylus Gray (Squamata: Gekkonidae) from northern Mizoram, North-east India.

A new species of Cyrtodactylus is described from Vairengte town, situated in the Kolasib District of Mizoram State, north-eastern India. The new species is found to be a member of Indo-Burman Cyrtodactylus khasiensis clade based on ND2 gene sequences and morphological parameters, such as number of precloacal pores, mid-ventral scale rows, paravertebral tubercles on the trunk, dorsal tubercle rows, subdigital lamellae on pes and subcaudal scalation, making it the sixth endemic Cyrtodactylus from Mizoram and twenty second from north-east India. Moreover, phylogenetic evidence suggests the new species to be sister to the recently described C. aaronbaueri, and morphological analyses also reveal marginal separation between the two species based on the PCA of infralabials, lamellae on fingers and toes, paravertebral tubercles on the trunk, and dorsal tubercle rows.

Bench to Bedside: New Therapeutic Approaches with Extracellular Vesicles and Engineered Biomaterials for Targeting Therapeutic Resistance of Cancer Stem Cells.

Cancer has recently been the second leading cause of death worldwide, trailing only cardiovascular disease. Cancer stem cells (CSCs), represented as tumor-initiating cells (TICs), are mainly liable for chemoresistance and disease relapse due to their self-renewal capability and differentiating capacity into different types of tumor cells. The intricate molecular mechanism is necessary to elucidate CSC's chemoresistance properties and cancer recurrence. Establishing efficient strategies for CSC maintenance and enrichment is essential to elucidate the mechanisms and properties of CSCs and CSC-related therapeutic measures. Current approaches are insufficient to mimic the in vivo chemical and physical conditions for the maintenance and growth of CSC and yield unreliable research results. Biomaterials are now widely used for simulating the bone marrow microenvironment. Biomaterial-based three-dimensional (3D) approaches for the enrichment of CSC provide an excellent promise for future drug discovery and elucidation of molecular mechanisms. In the future, the biomaterial-based model will contribute to a more operative and predictive CSC model for cancer therapy. Design strategies for materials, physicochemical cues, and morphology will offer a new direction for future modification and new methods for studying the CSC microenvironment and its chemoresistance property. This review highlights the critical roles of the microenvironmental cues that regulate CSC function and endow them with drug resistance properties. This review also explores the latest advancement and challenges in biomaterial-based scaffold structure for therapeutic approaches against CSC chemoresistance. Since the recent entry of extracellular vesicles (EVs), cell-derived nanostructures, have opened new avenues of investigation into this field, which, together with other more conventionally studied signaling pathways, play an important role in cell-to-cell communication. Thus, this review further explores the subject of EVs in-depth. This review also discusses possible future biomaterial and biomaterial-EV-based models that could be used to study the tumor microenvironment (TME) and will provide possible therapeutic approaches. Finally, this review concludes with potential perspectives and conclusions in this area.

A new bent-toed gecko (Cyrtodactylus Gray: Squamata: Gekkonidae) from the state of Mizoram, India.

Herein we describe a new species of Cyrtodactylus from Lunglei District in the state of Mizoram, India. Based on morphology and ND2 gene sequences, the species was found to be a member of the Cyrtodactylus khasiensis group. The species can be identified by its moderate size (adult SVL 64.975.1 mm) with rounded, bluntly conical and feebly keeled dorsal tubercles in 2428 longitudinal rows; 3240 paravertebral tubercles between the level of the axilla and the level of the groin; 3743 mid-ventral scale rows; 35 precloacal pores in males and 57 pitted precloacal scales in females; 1618 subdigital lamellae under IV toe; no single row of transversely enlarged subcaudal scales; dorsal markings are dark brown, irregular and distinct; tail with alternating dark and light bands.

Postcolonial pandemic publics: examining social media health promotion in India during the COVID-19 crisis.

Affordances offered by new media platforms are perceived as revolutionary instruments for removing the inequities of access to health promotion and communication. However, the production and dissemination of health promotional material on digital platforms does not necessarily translate into uniform access across diverse demographics. This article addresses the lacuna when it comes to analyzing Health Promotion initiatives in India, with a specific focus on the governmental publicity carried out on social media during the four phases of COVID-19 national lockdown between 24 March and 31 May 2020. Our intervention examines how governmental social media health promotion in India played a key role in shaping the 'outbreak narrative' during the lockdown across different levels of social and economic privilege. Through a combination of quantitative data analysis and qualitative interview methods, this article analyzes the circulation and impact of official publicity in online and offline spaces, during the COVID-19 lockdown in India. Resultant findings allow for a comprehensive assessment of whether such publicity contributed to democratized citizen science discourses: enabling social protection measures for vulnerable majorities or potentially reified the existing privileges of the economically and socially affluent minority. We find that health promotion campaigns during a pandemic must focus on reaching the widest possible audience in the most efficient manner. Specifically, in the Indian context, health promotion through mass-media like Television and Radio, and participatory media platforms needed to be implemented in tandem with new media platforms, to achieve required engagement with vulnerable communities on key health issues.

The odd one in: re-diagnosis and phylogenetic placement of the Assam Day Gecko, Cnemaspis assamensis Das amp; Sengupta 2000 (Squamata: Gekkonidae).

Herein we provide new information on Cnemaspis assamensis, the only species of Cnemaspis known from north-eastern India. Based on five new samples, morphological parameters are described. The species was found to have pre-cloacal and femoral pores, not accounted for in the original description. Genetic assessment of the species was made using a 914 bp fragment of the ND2 mitochondrial gene and the species was recovered as the sister taxon of the C. podihuna clade from Sri Lanka.

Identification and characterization of metamorphic proteins: Current and future perspectives.

Proteins that can reversibly alternate between distinctly different folds under native conditions are described as being metamorphic. The "metamorphome" is the collection of all metamorphic proteins in the proteome, but it remains unknown the extent to which the proteome is populated by this class of proteins. We propose that uncovering the metamorphome will require a synergy of computational screening of protein sequences to identify potential metamorphic behavior and validation through experimental techniques. This perspective discusses computational and experimental approaches that are currently used to predict and characterize metamorphic proteins as well as the need for developing improved methodologies. Since metamorphic proteins act as molecular switches, understanding their properties and behavior could lead to novel applications of these proteins as sensors in biological or environmental contexts.

Involvement of extracellular vesicles in aging process and their beneficial effects in alleviating aging-associated symptoms.

Aging is a gradual and unavoidable physiological phenomenon that manifests in the natural maturation process and continues to progress from infanthood to adulthood. Many elderly people suffer from aging-associated hematological and nonhematological disorders. Recent advances in regenerative medicine have shown new revolutionary paths of treating such diseases using stem cells; however, aging also affects the quality and competence of stem and progenitor cells themselves and ultimately directs their death or apoptosis and senescence, leading to a decline in their regenerative potential. Recent research works show that extracellular vesicles (EVs) isolated from different types of stem cells may provide a safe treatment for aging-associated disorders. The cargo of EVs comprises packets of information in the form of various macromolecules that can modify the fate of the target cells. To harness the true potential of EVs in regenerative medicine, it is necessary to understand how this cargo contributes to the rejuvenation of aged stem and progenitor populations and to identify the aging-associated changes in the macromolecular profile of the EVs themselves. In this review, we endeavor to summarize the current knowledge of the involvement of EVs in the aging process and delineate the role of EVs in the reversal of aging-associated phenotypes. We have also analyzed the involvement of the molecular cargo of EVs in the generation of aging-associated disorders. This knowledge could not only help us in understanding the mechanism of the aging process but could also facilitate the development of new cell-free biologics to treat aging-related disorders in the future.

Differential expression of retinoic acid alpha and beta receptors in neuronal progenitors generated from human embryonic stem cells in response to TTNPB (a retinoic acid mimetic).

Retinoic acid (RA), an active metabolite of vitamin A, plays a critical role in the morphogenesis and differentiation of various tissues, especially in the central nervous system. RA is the most commonly used morphogen for the differentiation of human embryonic stem cells (hESCs) into neuronal progenitor cells (NPCs), an abundant source of healthy neuronal tissues for regenerative therapy. During the differentiation process, the activity of RA is governed by the involvement of RA receptor subtypes (RAR α, ß, and γ) and their isoforms in the nucleus. However, little is known about the involvement of specific RAR subtypes during neuronal differentiation in humans. It is essential to elucidate the dynamic function of different RAR subtypes and their influence on the phenotypic outcome. Here in this study, we used TTNPB, an analog and stabilized form of retinoic acid that potently and selectively activates retinoic acid receptors. Here we determined the optimum concentration of TTNPBfor the efficient generation of early NPCs from hESCs. Using the optimized concentration of -TTNPB, we found that RARα is the functionally dominant subtype and controls the RA-mediated neurogenesis of hESCs. Importantly, we also found that the RARγ subtype also played a role in neuronal differentiation. In contrast, the RARß subtype negatively correlates with neuronal differentiation. Therefore, pharmacological inhibition of RARß in the TTNPB-mediated differentiation process could be used as a strategy to generate a large number of NPCs in vitro. In summary, our results show that RARα and RARγ play a vital role in the TTNPB-mediated neuronal differentiation of hESCs, -whereas RARß acts as a negative regulator.

Extracellular vesicles: Mediators of embryo-maternal crosstalk during pregnancy and a new weapon to fight against infertility.

In modern-day life, infertility is one of the major issues that can affect an individual, both physically and psychologically. Several anatomical, physiological, and genetic factors might contribute to the infertility of an individual. Intercellular communication between trophectoderm and endometrial epithelium triggers successful embryo implantation and thereby establishes pregnancy. Recent studies demonstrate that Extracellular vesicles (EVs) are emerging as one of the crucial components that are involved in embryo-maternal communication and promote pregnancy. Membrane-bound EVs release several secreted factors within the uterine fluid, which mediates an intermolecular transfer of EVs' cargos between blastocysts and endometrium. Emerging evidences indicate that several events like imbalance in the release of endometrial or placenta-derived EVs (exosomes/MVs), uptake of their content, failure of embryo selection might lead to implantation failure. Here in this review, we have discussed the current knowledge of the involvement of EVs in maternal-fetal communications during implantation and also highlighted the EVs' rejuvenating ability to overcome infertility-related issues. We also discussed the alteration of the EVs' cargo in different pathological conditions that lead to infertility. Therefore, this review would give a better understanding of EVs' contribution in successful embryo implantation, which could help in the development of new diagnostic tools and cell-free biologics to improve the in vivo reproductive process and to treat infertility by restoring normal reproductive functions.

Sequence-Based Prediction of Metamorphic Behavior in Proteins.

An increasing number of proteins have been demonstrated in recent years to adopt multiple three-dimensional folds with different functions. These metamorphic proteins are characterized by having two or more folds with significant differences in their secondary structure, in which each fold is stabilized by a distinct local environment. So far, ∼90 metamorphic proteins have been identified in the Protein Databank, but we and others hypothesize that a far greater number of metamorphic proteins remain undiscovered. In this work, we introduce a computational model to predict metamorphic behavior in proteins using only knowledge of the sequence. In this model, secondary structure prediction programs are used to calculate diversity indices, which are measures of uncertainty in predicted secondary structure at each position in the sequence; these are then used to assign protein sequences as likely to be metamorphic versus monomorphic (i.e., having just one fold). We constructed a reference data set to train our classification method, which includes a novel compilation of 136 likely monomorphic proteins and a set of 201 metamorphic protein structures taken from the literature. Our model is able to classify proteins as metamorphic versus monomorphic with a Matthews correlation coefficient of ∼0.36 and true positive/true negative rates of ∼65%/80%, suggesting that it is possible to predict metamorphic behavior in proteins using only sequence information.

Synthesis of Simple 3,3-Diarylazetidines from N-Boc-3-arylazetidinols Using Friedel-Crafts Arylation Conditions.

A synthesis of 3,3-diarylazetidines from N-Boc-3-aryl-3-azetidinols using Friedel-Crafts arylation conditions with AlCl3 is described. A series of substituted diarylazetidines were readily prepared and isolated as the oxalate salts in high yield and high purity. The 3,3-diarylazetidine oxalates were then easily converted into N-alkyl and N-acyl analogues (RX, NaHCO3/DMF/100 °C) in high overall yields.

Another new Cyrtodactylus (Squamata: Gekkonidae) from Guwahati, Assam, India.

We describe a new species of Cyrtodactylus from Guwahati city in the state of Assam, India and provide additional data on the recently described Cyrtodactylus guwahatiensis. Cyrtodactylus urbanus sp. nov. falls in the newly defined khasiensis group within the Indo-Burma clade of Cyrtodactylus and is the poorly supported sister taxon to Cyrtodactylus khasiensis. The new species differs from other members of the khasiensis group in mitochondrial sequence data (12.5-17.1 % uncorrected pairwise ND2 sequence divergence) as well as aspects of morphology including the number and arrangement of precloacal pores in males, the number of mid-ventral scales and paravertebral tubercles, and colour pattern. This is the second Cyrtodactylus endemic to the Guwahati region, the fourth from Assam and the twelfth from Northeast India.

A new species of Polypedates Tschudi, 1838 (Amphibia: Anura: Rhacophoridae) from West Bengal State, Eastern India.

A new species of frog belonging to the genus Polypedates Tschudi is described from the state of West Bengal, Eastern India. A mid-sized frog, SVL ranges from 47.9-53.6 mm in males and 72.0 mm in the single female. The species is diagnosable in showing the following suite of characters: digits lack webbing, inner and outer metacarpal tubercles present; no dermal fold on forearm; toes webbed, webbing formula I1-1 II0.5-2III1-2IV2-0.5V; an inner metatarsal tubercle present; tibio-tarsal articulation reaches between eye and nostril; and skin on forehead co-ossified to cranium. Additionally, males possess paired vocal sacs. The new species is compared with known species of the genus Polypedates.

Breaking the barricade of oral chemotherapy through polysaccharide nanocarrier.

Oral chemotherapy is the most preferred drug administration method due to non-invasive administration, more convenient, low healthcare cost, and patient compliance in comparison to intravenous chemotherapy. However, oral chemotherapy poses numerous hurdles to drug absorption through the gastrointestinal tract. Recently, nanocarriers have been extensively used for delivering anticancer drugs orally. Nanocarriers present distinctive advantages that comprise aiding drug dissolution owing to high surface to volume ratio, surface modifiability, protecting drugs from the harsh gastrointestinal environments and other features, all of which contribute to enhanced drugs bioavailability. Nanocarriers based on polysaccharides have emerged as the favored choice owing to their low/non-toxicity, biodegradability, and biocompatibility. In the last decade, the research on oral delivery of anticancer drug using polysaccharide nanocarrier has diversified in many fields. Yet there is no report that summaries these advances. This article aims to bridge that lacuna. In this review article, we have discussed the problems associated with oral chemotherapy and conquer these through polysaccharide nanocarriers. This review also provides a general idea on the current developments in polysaccharide nanocarrier for oral bioavailability enhancement of anticancer drugs.

A review of the relationships of Xenochrophis cerasogaster Cantor, 1839 (Serpentes: Colubridae) to its congeners.

We sampled snakes of the genus Xenochrophis from across Northeast India. The snakes were evaluated for both morphological and molecular parameters. Phylogenetic relationship was reconstructed using mitochondrial genes (Cytb, 12s rRNA, ND4). The genus Xenochrophis was found to be paraphyletic, X. piscator complex and X. punctulatus form a single clade with Atretium schistosum as their sister taxon. X. cerasogaster forms a distinct lineage. X. vittatus and X. trianguligerus are related to the genus Rhabdophis. Herein it is recommended that X. piscator complex, i.e. X. asperrimus, X. flavipunctatus, X. melanzostus, X. piscator, X. sanctijohannis, X. schnurrenbergeri and X. tytleri, as well as X. punctulatus be reallocated to the genus Fowlea.

Synthesis, hepatotoxic evaluation and antipyretic activity of nitrate ester analogs of the acetaminophen derivative SCP-1.

A series of nitrate ester analogues of the acetaminophen derivative SCP-1 were prepared by triflic acid catalyzed O-acylation of SCP-1 with chloroalkanoyl chlorides followed by nitration with silver nitrate. The chloroesters and corresponding nitrate esters were obtained in high yields. Preliminary hepatotoxicity studies revealed nitrate esters 5b (MD-38) and 5c (MD-39) to be well tolerated by human hepatocytes and had little effect on the three cytochrome P450 enzymes tested (CYP3A4, CYP2E1 and CYP2D6). In addition, the nitrate ester 5c (MD-39) exhibited antipyretic activity similar to acetaminophen.

Molecular Insights into Human Hereditary Apolipoprotein A-I Amyloidosis Caused by the Glu34Lys Mutation.

Hereditary apolipoprotein A-I (apoA-I) amyloidosis is a life-threatening incurable genetic disorder whose molecular underpinnings are unclear. In this disease, variant apoA-I, the major structural and functional protein of high-density lipoprotein, is released in a free form, undergoes an α-helix to intermolecular cross-ß-sheet conversion along with a proteolytic cleavage, and is deposited as amyloid fibrils in various organs, which can cause organ damage and death. Glu34Lys is the only known charge inversion mutation in apoA-I that causes human amyloidosis. To elucidate the structural underpinnings of the amyloidogenic behavior of Glu34Lys apoA-I, we generated its recombinant globular N-terminal domain (residues 1-184) and compared the conformation and dynamics of its lipid-free form with those of two other naturally occurring apoA-I variants, Phe71Tyr (amyloidogenic) and Leu159Arg (non-amyloidogenic). All variants showed reduced structural stability and altered aromatic residue packing. The greatest decrease in stability was observed in the non-amyloidogenic variant, suggesting that amyloid formation is driven by local structural perturbations at sensitive sites. Molecular dynamics simulations revealed local helical unfolding and suggested that transient opening of the Trp72 side chain induced mutation-dependent structural perturbations in a sensitive region, including the major amyloid hot spot residues Leu14-Leu22. We posit that a shift from the "closed" to the "open" orientation of the Trp72 side chain modulates structural protection of amyloid hot spots, suggesting a previously unknown early step in the protein misfolding pathway.