SARS-CoV-2 antibody magnitude and detectability are driven by disease severity, timing, and assay.

Serosurveillance studies are critical for estimating SARS-CoV-2 transmission and immunity, but interpretation of results is currently limited by poorly defined variability in the performance of antibody assays to detect seroreactivity over time in individuals with different clinical presentations. We measured longitudinal antibody responses to SARS-CoV-2 in plasma samples from a diverse cohort of 128 individuals over 160 days using 14 binding and neutralization assays. For all assays, we found a consistent and strong effect of disease severity on antibody magnitude, with fever, cough, hospitalization, and oxygen requirement explaining much of this variation.

TRP Channel Involvement in Salivary Glands-Some Good, Some Bad.

Salivary glands secrete saliva, a mixture of proteins and fluids, which plays an extremely important role in the maintenance of oral health. Loss of salivary secretion causes a dry mouth condition, xerostomia, which has numerous deleterious consequences including opportunistic infections within the oral cavity, difficulties in eating and swallowing food, and problems with speech. Secretion of fluid by salivary glands is stimulated by activation of specific receptors on acinar cell plasma membrane and is mediated by an increase in cytosolic [Ca] ([Ca]).

PI3K pathway is involved in ERK signaling cascade activation by histamine H2R agonist in HEK293T cells.

Background: Histamine, through histamine H2 receptor (H2R), modulates different biological processes, involving the modulation of PI3K/AKT/mTOR and RAS/RAF/MEK/ERK pathways. Many evidences have demonstrated the existence and importance of the crossregulation between these two signaling pathways. The aim of the present work was to determine the molecular mechanisms leading to PI3K and ERK pathways modulation induced by the H2R agonist amthamine and to evaluate the possible interplay between them.

Calcium signalling in salivary gland physiology and dysfunction.

Studies over the past four decades have established that Ca(2+) is a critical factor in control of salivary gland function and have led to identification of the critical components of this process. The major ion transport mechanisms and ion channels that are involved in fluid secretion have also been established. The key event in activation of fluid secretion is an increase in [Ca(2+) ]i triggered by inositol 1,4,5-trisphosphate (IP3 )-induced release of Ca(2+) from ER via the IP3 receptor (IP3 R).

Ca²⁺ signaling and regulation of fluid secretion in salivary gland acinar cells.

Neurotransmitter stimulation of plasma membrane receptors stimulates salivary gland fluid secretion via a complex process that is determined by coordinated temporal and spatial regulation of several Ca(2+) signaling processes as well as ion flux systems. Studies over the past four decades have demonstrated that Ca(2+) is a critical factor in the control of salivary gland function. Importantly, critical components of this process have now been identified, including plasma membrane receptors, calcium channels, and regulatory proteins.

Exploiting the head and neck cancer oncogenome: widespread PI3K-mTOR pathway alterations and novel molecular targets.

Two studies published in this issue of Cancer Discovery describe the emerging mutational landscape of head and neck squamous cell carcinomas (HNSCC) and their genomic and epigenetic alterations, thus identifying novel actionable cancer drivers and predictive biomarkers for targeted therapies. Most genomic alterations in HNSCC converge in a handful of molecular pathways, resulting in cell-cycle deregulation, genomic instability, cell differentiation defects, and persistent mitogenic signaling, the latter involving aberrant phosphoinositide 3-kinase (PI3K)/mTOR pathway activation, thereby rendering HNSCC responsive to PI3K/mTOR inhibitors. Cancer Discov; 3(7); 722-5.

Control of the epithelial stem cell epigenome: the shaping of epithelial stem cell identity.

The squamous epithelium covering the skin and oral mucosa relies on epithelial stem cells for tissue renewal. Dynamic changes in DNA methylation, histone methylation and acetylation, and higher order chromatin structure are required to preserve their self-renewal capacity while orchestrating the timely execution of cell differentiation programs. This complex network of epigenetic modifications shapes the epithelial stem cell identity and fate.

Decreased lymphangiogenesis and lymph node metastasis by mTOR inhibition in head and neck cancer.

Despite our improved understanding of cancer, the 5-year survival rate for head and neck squamous cell carcinomas (HNSCC) patients remains relatively unchanged at 50% for the past three decades. HNSCCs often metastasize to locoregional lymph nodes, and lymph node involvement represents one of the most important prognostic factors of poor clinical outcome. Among the multiple dysregulated molecular mechanism in HNSCCs, emerging basic, preclinical, and clinical findings support the importance of the mTOR signaling route in HNSCC progression.

Signaling circuitries controlling stem cell fate: to be or not to be.

The integration of extrinsic and intrinsic signals is required to preserve the self-renewal and tissue regenerative capacity of adult stem cells, while protecting them from malignant conversion or loss of proliferative potential by death, differentiation or senescence. Here we review emerging signaling circuitries regulating stem cell fate, with emphasis on epithelial stem cells. Wnt, mTOR, GPCRs, Notch, Rho GTPases, YAP and DNA and histone methylases are some of the mechanisms that allow stem cells to balance their regenerative potential and the initiation of terminal differentiation programs, guaranteeing appropriate tissue homeostasis.

Keeping the epidermal stem cell niche in shape.

Recently in Nature Cell Biology,Connelly et al. (2010) identified biomechanical sensing mechanisms that link the physical shape of the stem cell microenvironment to epithelial stem cell fate decisions. Ultimately, the integration of extrinsic and intrinsic signals controls stem cell self-renewal or differentiation.

Isolation of whole mononuclear cells from peripheral blood and cord blood.

Peripheral blood is the primary source of lymphoid cells for investigation of the human immune system. Its use is facilitated by Ficoll-Hypaque density gradient centrifugation-a simple and rapid method of purifying peripheral blood mononuclear cells (PBMC) that takes advantage of the density differences between mononuclear cells and other elements found in the blood sample. Thus, cells are distributed in the solution in layers based on the differences in their density/size.

Matrix metalloproteinases.

Matrix metalloproteinases are a class of enzymes that play an important role in the remodeling of the extracellular matrix in development and cancer metastasis. This unit describes a set of methods--cell-mediated dissolution of type-1 collagen fibrils, direct and reverse zymography, enzyme capture based on alpha2-macroglobulin and TIMP-1 and -2, and demonstration of cryptic thiol groups in metalloproteinase precursors--that are used to characterize the functions of matrix metalloproteinases and their inhibitors.

Isolation of whole mononuclear cells from peripheral blood and cord blood.

Peripheral blood is the primary source of lymphoid cells for investigations of the human immune system. Its use is facilitated by the Ficoll-Hypaque density gradient centrifugation method described here. It is a simple and rapid method of purifying peripheral blood mononuclear cells (PBMC) that takes advantage of the density differences between mononuclear cells and other elements found in the blood sample.

Matrix metalloproteinases.

Matrix metalloproteinases are a class of enzymes that play an important role in the remodeling of the extracellular matrix in development and cancer metastasis. This unit describes a set of methods-cell-mediated dissolution of type I collagen fibrils, direct and reverse zymography, enzyme capture based on a-2 macroglubulin and TIMP-1 and -2, and demonstration of crytic thiol groups in metalloproteinase precursors-that are used to characterize the functions of matrix metalloproteinases and their inhibitors.

Preparation of endothelial cells.

Endothelial cells, which line blood vessels, can be prepared from a variety of tissues. They are frequently prepared from the umbilical vein, which is relatively easy to obtain. The procedure is clearly described and provides a large population of highly purified endothelial cells.

Invasion assays.

Basement membrane is a thin extracellular matrix that underlies epithelia and endothelia and separates them from the stroma. Tumor cells must cross this membrane to invade stroma and establish distant metastases. They do this by producing proteases that degrade the matrix.

Preparation of gelled substrates.

Gelled substrates can be used for a variety of in vitro and in vivo experiments. A type I collagen gelled substrate will promote cell growth and differentiation. Gelled Matrigel substrate promotes the survival of explanted cells and tissues and the differentiation of a variety of epithelial and endothelial cell types in vitro and to assess angiogenesis and increase tumor growth in vivo.

Preparation of basement membrane components from EHS tumors.

This unit describes methods for passaging and harvesting the basement membrane matrix-producing EHS tumor and for the subsequent isolation of a crude mixture of basement membrane components termed Matrigel, which promotes the differentiation of a variety of epithelial, endothelial, and neuronal cells. Procedures for the isolation of the adhesive glycoprotein laminin-1 and of type IV collagen are also included. Support protocols cover the maintenance and harvesting of EHS tumors in mice and maintenance of mice on a lathrogenic diet.

Rapid development of salivary gland carcinomas upon conditional expression of K-ras driven by the cytokeratin 5 promoter.

We have used a recently described model in which a ras oncogene is expressed in cytokeratin 5 (K5)-expressing cells on doxycycline administration to explore the effects of this oncogene in salivary glands of adult mice. Inducible expression of a mutated K-ras gene under the control of the K5 promoter led to the development of hyperplastic and dysplastic epithelial lesions and carcinomas, with an incidence of 100% and a minimum latency of a week. All major salivary glands were affected, as well as a set of previously undescribed buccal accessory salivary glands located on the apex of the masseter muscle, close to the oral angle.

Regulation of the transcriptional activity of c-Fos by ERK. A novel role for the prolyl isomerase PIN1.

The activation of the activating protein-1 (AP-1) family of transcription factors, including c-Fos and c-Jun family members, is one of the earliest nuclear events induced by growth factors that stimulate extracellular signal-regulated kinases (ERKs). In the case of c-Fos, the activation of ERK leads to an increased expression of c-fos mRNA. In turn, we have recently shown that ERK phosphorylates multiple residues within the carboxylterminal transactivation domain (TAD) of c-Fos, thus resulting in its increased transcriptional activity.

Conditional expression of K-ras in an epithelial compartment that includes the stem cells is sufficient to promote squamous cell carcinogenesis.

Ras genes are the most frequently mutated oncogenes in human cancer. However, the contribution of ras to tumor initiation still is unclear because ras expression in primary cells can cause cell cycle arrest and even cell death by apoptosis. Furthermore, when expressed in the epidermis of mice, mutant ras promotes the formation of benign papillomas, only few of which will progress into carcinomas.

Autocrine activation of an osteopontin-CD44-Rac pathway enhances invasion and transformation by H-RasV12.

Activated forms of Ras family members are prevalent in many cancers where Ras mutants transduce signals essential for transformation, angiogenesis, invasion and metastasis. As a cancer progression model, we used NIH3T3 cells to explore the mechanism of Ras-induced tumorigenesis. Ras family mutants H-RasV12 and Rit79L strongly induced foci formation, while Rho family mutants RhoA-QL, Rac1-QL and Cdc42-QL were less effective.

Does dysregulated expression of a deregulated viral GPCR trigger Kaposi's sarcomagenesis?

In 1994, the Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) was identified as the etiologic agent of Kaposi's sarcoma (KS). KSHV has since been associated with two additional AIDS-related malignancies: primary effusion lymphomas (PEL) and multicentric Castleman's disease (MCD). Although molecular characterization of the KSHV genome has revealed several candidate oncogenes, infection with KSHV alone is not sufficient to cause KS, suggestive of an accomplice in KS initiation.

Alterations in granule matrix and cell surface of focal adhesion kinase-deficient mast cells.

Focal adhesion kinase (FAK) is a nonreceptor protein tyrosine kinase that plays an important role in many cellular processes and is tyrosine phosphorylated after FcepsilonRI aggregation in mast cells. In mice, null mutation of the fak gene results in a lethal phenotype in which the embryos fail to develop past day 8.5 of gestation.