Type II taste cells participate in mucosal immune surveillance.

The oral microbiome is second only to its intestinal counterpart in diversity and abundance, but its effects on taste cells remains largely unexplored. Using single-cell RNASeq, we found that mouse taste cells, in particular, sweet and umami receptor cells that express taste 1 receptor member 3 (Tas1r3), have a gene expression signature reminiscent of Microfold (M) cells, a central player in immune surveillance in the mucosa-associated lymphoid tissue (MALT) such as those in the Peyer's patch and tonsils. Administration of tumor necrosis factor ligand superfamily member 11 (TNFSF11; also known as RANKL), a growth factor required for differentiation of M cells, dramatically increased M cell proliferation and marker gene expression in the taste papillae and in cultured taste organoids from wild-type (WT) mice.

Sweet Taste Signaling: The Core Pathways and Regulatory Mechanisms.

Sweet taste, a proxy for sugar-derived calories, is an important driver of food intake, and animals have evolved robust molecular and cellular machinery for sweet taste signaling. The overconsumption of sugar-derived calories is a major driver of obesity and other metabolic diseases. A fine-grained appreciation of the dynamic regulation of sweet taste signaling mechanisms will be required for designing novel noncaloric sweeteners with better hedonic and metabolic profiles and improved consumer acceptance.

Nkx2-2 expressing taste cells in endoderm-derived taste papillae are committed to the type III lineage.

In mammals, multiple cell-signaling pathways and transcription factors regulate development of the embryonic taste system and turnover of taste cells in the adult stage. Using single-cell RNA-Seq of mouse taste cells, we found that the homeobox-containing transcription factor Nkx2-2, a target of the Sonic Hedgehog pathway and a key regulator of the development and regeneration of multiple cell types in the body, is highly expressed in type III taste cells but not in type II or taste stem cells. Using in situ hybridization and immunostaining, we confirmed that Nkx2-2 is expressed specifically in type III taste cells in the endoderm-derived circumvallate and foliate taste papillae but not in the ectoderm-derived fungiform papillae.

Truncated Thioredoxin Peptides Serves as an Efficient Fusion Tag for Production of Proinsulin.

Background: Insulin is a peptide hormone used for regulating blood glucose levels. Human insulin market is projected to grow at a rate of 12.5% annually.

Gli3 is a negative regulator of Tas1r3-expressing taste cells.

Mouse taste receptor cells survive from 3-24 days, necessitating their regeneration throughout adulthood. In anterior tongue, sonic hedgehog (SHH), released by a subpopulation of basal taste cells, regulates transcription factors Gli2 and Gli3 in stem cells to control taste cell regeneration. Using single-cell RNA-Seq we found that Gli3 is highly expressed in Tas1r3-expressing taste receptor cells and Lgr5+ taste stem cells in posterior tongue.

Whole transcriptome profiling of taste bud cells.

Analysis of single-cell RNA-Seq data can provide insights into the specific functions of individual cell types that compose complex tissues. Here, we examined gene expression in two distinct subpopulations of mouse taste cells: Tas1r3-expressing type II cells and physiologically identified type III cells. Our RNA-Seq libraries met high quality control standards and accurately captured differential expression of marker genes for type II (e.

MOAP-1 Mediates Fas-Induced Apoptosis in Liver by Facilitating tBid Recruitment to Mitochondria.

Fas apoptotic signaling regulates diverse physiological processes. Acute activation of Fas signaling triggers massive apoptosis in liver. Upon Fas receptor stimulation, the BH3-only protein Bid is cleaved into the active form, tBid.

Taste cell-expressed α-glucosidase enzymes contribute to gustatory responses to disaccharides.

The primary sweet sensor in mammalian taste cells for sugars and noncaloric sweeteners is the heteromeric combination of type 1 taste receptors 2 and 3 (T1R2+T1R3, encoded by Tas1r2 and Tas1r3 genes). However, in the absence of T1R2+T1R3 (e.g.

Amiloride-Insensitive Salt Taste Is Mediated by Two Populations of Type III Taste Cells with Distinct Transduction Mechanisms.

Unlabelled: Responses in the amiloride-insensitive (AI) pathway, one of the two pathways mediating salty taste in mammals, are modulated by the size of the anion of a salt. This "anion effect" has been hypothesized to result from inhibitory transepithelial potentials (TPs) generated across the lingual epithelium as cations permeate through tight junctions and leave their larger and less permeable anions behind (Ye et al., 1991).

Comparative cytomorphometric analysis of oral mucosal cells in normal, tobacco users, oral leukoplakia and oral squamous cell carcinoma.

Background: Squamous cell carcinoma (SCC) is the third most common cause of oral morbidity in India despite the numerous advances made in the treatment protocol.

Aim: To compare the cytomorphometric changes of oral mucosal cells in normal subjects (Group I) with that of tobacco users without any lesion (Group II), tobacco users with oral leukoplakia (Group III), and tobacco users with oral SCC (Group IV) through a semi-automated image analysis system.

Materials And Methods: Oral mucosal cells collected from study subjects (n = 100) stained using rapid Papanicolaou stain.

Estimation of Salivary Glucose and Glycogen Content in Exfoliated Buccal Mucosal Cells of Patients with Type II Diabetes Mellitus.

Background: Diabetes mellitus is a common metabolic disorder which shows an increasing incidence worldwide. Constant monitoring of blood glucose in diabetic patient is required which involves painful invasive techniques. Saliva is gaining acceptance as diagnostic tool for various systemic diseases which can be collected noninvasively and by individuals with limited training.

Discovery of PAT-1102, a novel, potent and orally active histone deacetylase inhibitor with antitumor activity in cancer mouse models.

Aim: Histone deacetylase (HDAC) inhibitors are a class of drugs that modulate transcriptional activity in cells and are known to induce cell-cycle arrest and angiogenesis, the major components of tumor cell proliferation. The aim of the present study was to characterize a novel hydroxamic acid-based HDAC inhibitor, PAT-1102, and determine its efficacy and tolerability in pre-clinical models.

Materials And Methods: HDAC enzyme inhibition was measured using HeLa cell nuclear extracts, and recombinant HDAC enzymes.

Zebrafish as an in vivo high-throughput model for genotoxicity.

Compounds routinely used to increase the quality of life and combat disease undergo stringent potency and biosafety tests before approval. However, based on the outcome of ongoing research, new norms need to be effected to ensure that the compounds conform to biosafety at all target levels of activity. Whereas in vitro tests used to assess biosafety lack the potency and the translational attribute of a whole animal, mammalian preclinical models are expensive and time exhaustive.

Validation of a human cell based high-throughput genotoxicity assay 'Anthem's Genotoxicity screen' using ECVAM recommended lists of genotoxic and non-genotoxic chemicals.

A novel high throughput-enabled human cell based screen, Anthem's Genotoxicity screen, was developed to achieve higher specificity for predicting in vivo genotoxins by an in vitro method. The assay employs engineered human colon carcinoma cell line; HCT116 cells that are stably engineered with three promoter-reporter cassettes such that an increased reporter activity reflects the activation of associated signaling events in a human cell. The current study focuses on the evaluation of sensitivity and specificity of Anthem's Genotoxicity screen using 62 compounds recommended by the European Centre for the Validation of Alternative Methods (ECVAM).

Norspermidine and novel Pd(II) and Pt(II) polynuclear complexes of norspermidine as potential antineoplastic agents against breast cancer.

Background: New strategies are needed for breast cancer treatment and one initial step is to test new chemotherapeutic drugs in breast cancer cell lines, to choose candidates for further studies towards clinical use.

Methodology And Findings: The cytotoxic effects of a biogenic polyamine analogue - norspermidine - and its trinuclear Pd(II) and Pt(II) complexes - Pd(3)NSpd(2) and Pt(3)NSpd(2), respectively - were investigated in one immortalized normal-like and three breast cancer cell lines. The normal-like MCF-10A cells were least sensitive to the compounds, while growth inhibition and cell death was observed in the cancer cell lines.

Glucose transporters and ATP-gated K+ (KATP) metabolic sensors are present in type 1 taste receptor 3 (T1r3)-expressing taste cells.

Although the heteromeric combination of type 1 taste receptors 2 and 3 (T1r2 + T1r3) is well established as the major receptor for sugars and noncaloric sweeteners, there is also evidence of T1r-independent sweet taste in mice, particularly so for sugars. Before the molecular cloning of the T1rs, it had been proposed that sweet taste detection depended on (a) activation of sugar-gated cation channels and/or (b) sugar binding to G protein-coupled receptors to initiate second-messenger cascades. By either mechanism, sugars would elicit depolarization of sweet-responsive taste cells, which would transmit their signal to gustatory afferents.

Fcγ receptor I alpha chain (CD64) expression in macrophages is critical for the onset of meningitis by Escherichia coli K1.

Neonatal meningitis due to Escherichia coli K1 is a serious illness with unchanged morbidity and mortality rates for the last few decades. The lack of a comprehensive understanding of the mechanisms involved in the development of meningitis contributes to this poor outcome. Here, we demonstrate that depletion of macrophages in newborn mice renders the animals resistant to E.

A soluble form of the pilus protein FimA targets the VDAC-hexokinase complex at mitochondria to suppress host cell apoptosis.

Inhibition of apoptotic response of host cells during an early phase of infection is a strategy used by many enteroinvasive bacterial pathogens to enhance their survival. Here, we report the identification of a soluble form of the pilus protein FimA from the culture supernatants of E. coli K1, Salmonella, and Shigella that can potently inhibit Bax-mediated release of cytochrome c from isolated mitochondria.

The hepatitis C virus core protein contains a BH3 domain that regulates apoptosis through specific interaction with human Mcl-1.

The hepatitis C virus (HCV) core protein is known to modulate apoptosis and contribute to viral replication and pathogenesis. In this study, we have identified a Bcl-2 homology 3 (BH3) domain in the core protein that is essential for its proapoptotic property. Coimmunoprecipitation experiments showed that the core protein interacts specifically with the human myeloid cell factor 1 (Mcl-1), a prosurvival member of the Bcl-2 family, but not with other prosurvival members (Bcl-X(L) and Bcl-w).

Baxbeta: a constitutively active human Bax isoform that is under tight regulatory control by the proteasomal degradation mechanism.

Although mRNAs of multiple isoforms of Bax, which encodes a central regulator of apoptosis signaling, have been reported, only Baxalpha protein has been well documented and studied. Baxalpha exists in latent form and is activated upon apoptosis induction through conformational changes. Here we demonstrate that Baxbeta protein is ubiquitously present among human cells, but its activity is restricted through stringent regulation by proteasomal degradation.

TRIM39 is a MOAP-1-binding protein that stabilizes MOAP-1 through inhibition of its poly-ubiquitination process.

Bax, a multi-domain pro-apoptotic Bcl-2 family member, is a key regulator for the release of apoptogenic factors from mitochondria. MOAP-1, which was first isolated from a screen for Bax-associating proteins, interacts with Bax upon apoptotic induction. MOAP-1 is a short-lived protein that is constitutively degraded by the ubiquitin-proteasome system.

Chelerythrine induces apoptosis through a Bax/Bak-independent mitochondrial mechanism.

Although murine embryonic fibroblasts (MEFs) with Bax or Bak deleted displayed no defect in apoptosis signaling, MEFs with Bax and Bak double knock-out (DKO) showed dramatic resistance to diverse apoptotic stimuli, suggesting that Bax and Bak are redundant but essential regulators for apoptosis signaling. Chelerythrine has recently been identified as a Bcl-xL inhibitor that is capable of triggering apoptosis via direct action on mitochondria. Here we report that in contrast to classic apoptotic stimuli, chelerythrine is fully competent in inducing apoptosis in the DKO MEFs.

Inhibition of ubiquitin-mediated degradation of MOAP-1 by apoptotic stimuli promotes Bax function in mitochondria.

The multidomain proapoptotic protein Bax of the Bcl-2 family is a central regulator for controlling the release of apoptogenic factors from mitochondria. Recent evidence suggests that the Bax-associating protein MOAP-1 may act as an effector for promoting Bax function in mitochondria. Here, we report that MOAP-1 protein is rapidly up-regulated by multiple apoptotic stimuli in mammalian cells.

MAP-1 is a mitochondrial effector of Bax.

Apoptotic stimuli induce conformational changes in Bax and trigger its translocation from cytosol to mitochondria. Upon assembling into the mitochondrial membrane, Bax initiates a death program through a series of events, culminating in the release of apoptogenic factors such as cytochrome c. Although it is known that Bax is one of the key factors for integrating multiple death signals, the mechanism by which Bax functions in mitochondria remains controversial.

Inhibition of apoptosis by Escherichia coli K1 is accompanied by increased expression of BclXL and blockade of mitochondrial cytochrome c release in macrophages.

Escherichia coli K1 survival in the blood is a critical step for the onset of meningitis in neonates. Therefore, the circulating bacteria are impelled to avoid host defense mechanisms by finding a niche to survive and multiply. Our recent studies have shown that E.