Major salivary gland output differs between users and non-users of specific medication categories

Background: The intake of medications is a major aetiologic factor of xerostomia. The purpose of this study was to investigate the selective influence of medication categories on flow rates of individual major salivary glands. Methods: The effect of each medication category on salivary flow rates was determined by dichotomy comparisons between users and non‐users. A total of 246 patients were included, 79 males and 167 females aged 13–92 years (mean 63 years). Of these, 200 used medications, which were grouped according to their category. A comprehensive medical and oral examination was performed. Both unstimulated and stimulated saliva was collected separately from the parotid and submandibular/sublingual glands. Results: Parotid flow rate was decreased among users of tranquillisers and sedatives (unstimulated flow), cardiovascular drugs and gastrointestinal drugs (stimulated flow). Submandibular/sublingual unstimulated output was lower in patients taking cardiovascular drugs, antihistamines, tranquillisers/sedatives and antidepressants, while the stimulated flow, in those taking cardiovascular drugs, antihistamines, tranquillisers/sedatives and gastrointestinal drugs. Conclusions: Users of many common medication categories display significantly reduced unstimulated and/or stimulated salivary flow rate from the major salivary glands compared with non‐users. A larger number of medication categories are associated with reductions in salivary flow rate from submandibular/sublingual glands than parotid glands.     

RNF5, a RING finger protein that regulates cell motility by targeting paxillin ubiquitination and altered localization

RNF5 is a RING finger protein found to be important in the growth and development of Caenorhabditis elegans. The search for RNF5-associated proteins via a yeast two-hybrid screen identified a LIM-containing protein in C. elegans which shows homology with human paxillin. Here we demonstrate that the human homologue of RNF5 associates with the amino-terminal domain of paxillin, resulting in its ubiquitination. RNF5 requires intact RING and C-terminal domains to mediate paxillin ubiquitination. Whereas RNF5 mediates efficient ubiquitination of paxillin in vivo, protein extracts were required for in vitro ubiquitination, suggesting that additional modifications and/or an associated E3 ligase assist RNF5 targeting of paxillin ubiquitination. Mutant Ubc13 efficiently inhibits RNF5 ubiquitination, suggesting that RNF5 generates polychain ubiquitin of the K63 topology. Expression of RNF5 increases the cytoplasmic distribution of paxillin while decreasing its localization within focal adhesions, where it is primarily seen under normal growth. Concomitantly, RNF5 expression results in inhibition of cell motility. Via targeting of paxillin ubiquitination, which alters its localization, RNF5 emerges as a novel regulator of cell motility.     

Phospholipase D1 production of phosphatidic acid at the plasma membrane promotes exocytosis of large dense-core granules at a late stage

Substantial efforts have recently been made to demonstrate the importance of lipids and lipid-modifying enzymes in various membrane trafficking processes, including calcium-regulated exocytosis of hormones and neurotransmitters. Among bioactive lipids, phosphatidic acid (PA) is an attractive candidate to promote membrane fusion through its ability to change membrane topology. To date, however, the biosynthetic pathway, the dynamic location, and actual function of PA in secretory cells remain unknown. Using a short interference RNA strategy on chromaffin and PC12 cells, we demonstrate here that phospholipase D1 is activated in secretagogue-stimulated cells and that it produces PA at the plasma membrane at the secretory granule docking sites. We show that phospholipase D1 activation and PA production represent key events in the exocytotic progression. Membrane capacitance measurements indicate that reduction of endogenous PA impairs the formation of fusion-competent granules. Finally, we show that the PLD1 short interference RNA-mediated inhibition of exocytosis can be rescued by exogenous provision of a lipid that favors the transition of opposed bi-layer membranes to hemifused membranes having the outer leaflets fused. Our findings demonstrate that PA synthesis is required during exocytosis to facilitate a late event in the granule fusion pathway. We propose that the underlying mechanism is related to the ability of PA to alter membrane curvature and promote hemi-fusion.     

Targeting neural circuitry in zebrafish using GAL4 enhancer trapping

We present a pilot enhancer trap screen using GAL4 to drive expression of upstream activator sequence (UAS)-linked transgenes in expression patterns dictated by endogenous enhancers in zebrafish. The patterns presented include expression in small subsets of neurons throughout the larval brain, which in some cases persist into adult. Through targeted photoconversion of UAS-driven Kaede and variegated expression of UAS-driven GFP in single cells, we begin to characterize the cellular components of labeled circuits.     

Cytokine storm in COVID-19: from viral infection to immune responses,diagnosis and therapy

The COVID-19 outbreak is emerging as a significant public health challenge. Excessive production of proinflammatory cytokines, also known as cytokine storm, is a severe clinical syndrome known to develop as a complication of infectious or inflammatory diseases. Clinical evidence suggests that the occurrence of cytokine storm in severe acute respiratory syndrome secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is closely associated with the rapid deterioration and high mortality of severe cases. In this review, we aim to summarize the mechanism of SARS-CoV-2 infection and the subsequent immunological events related to excessive cytokine production and inflammatory responses associated with ACE2-AngII signaling. An overview of the diagnosis and an update on current therapeutic regimens and vaccinations is also provided.     

Genetic diversity within Cryptosporidium parvum and related Cryptosporidium species.

To assess the genetic diversity in Cryptosporidium parvum, we have sequenced the small subunit (SSU) rRNA gene of seven Cryptosporidium spp., various isolates of C. parvum from eight hosts, and a Cryptosporidium isolate from a desert monitor. Phylogenetic analysis of the SSU rRNA sequences confirmed the multispecies nature of the genus Cryptosporidium, with at least four distinct species (C. parvum, C. baileyi, C. muris, and C. serpentis). Other species previously defined by biologic characteristics, including C. wrairi, C. meleagridis, and C. felis, and the desert monitor isolate, clustered together or within C. parvum. Extensive genetic diversities were present among C. parvum isolates from humans, calves, pigs, dogs, mice, ferrets, marsupials, and a monkey. In general, specific genotypes were associated with specific host species. A PCR-restriction fragment length polymorphism technique previously developed by us could differentiate most Cryptosporidium spp. and C. parvum genotypes, but sequence analysis of the PCR product was needed to differentiate C. wrairi and C. meleagridis from some of the C. parvum genotypes. These results indicate a need for revision in the taxonomy and assessment of the zoonotic potential of some animal C. parvum isolates.