Complexity of the human whole saliva proteome

Recent characterization of the whole saliva proteome led to contradictory picturesconcerning the complexity of its proteome. In this work, 110 proteins wereanalysed by mass spectrometry allowing the identification of 10 accessions previouslynot detected on protein two-dimensional maps, including myosin heavy chain(fast skeletal muscle, IIA and IIB), phosphatidylethanolamine binding protein,secretory actin-binding protein precursor and triosephosphate isomerase. Furthercomparison with available data demonstrated simultaneously a low diversity interms of variety of accessions and a high complexity in terms of number of proteinspots identifying the same accession, the two thirds of identified spots correspondingto amylases, cystatins and immunoglobulins. This diversity may be of interest inthe development of non invasive diagnostic tool for several disease (AU)

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Complexity of the human whole saliva proteome.

Recent characterization of the whole saliva proteome led to contradictory pictures concerning the complexity of its proteome. In this work, 110 proteins were analysed by mass spectrometry allowing the identification of 10 accessions previously not detected on protein two-dimensional maps, including myosin heavy chain (fast skeletal muscle, IIA and IIB), phosphatidylethanolamine binding protein, secretory actin-binding protein precursor and triosephosphate isomerase. Further comparison with available data demonstrated simultaneously a low diversity in terms of variety of accessions and a high complexity in terms of number of protein spots identifying the same accession, the two thirds of identified spots corresponding to amylases, cystatins and immunoglobulins. This diversity may be of interest in the development of non invasive diagnostic tool for several disease.

Preproglucagon mRNA expression in adult rat submandibular glands.

Salivary glands of various animal species have been reported to contain and suggested to produce glucagon or glucagon-like material, but the origin and the nature of this salivary peptide are still doubtful. The present study was undertaken to ascertain whether the glucagon gene is expressed in rat submandibular glands and in an immortalized murine cell line derived from salivary glands (SCA-9 cell line). For this purpose, total RNA was isolated from submandibular glands or cultured cells and submitted to reverse transcription. The cDNAs obtained were amplified by a nested polymerase chain reaction using preproglucagon primers. The results showed that the preproglucagon mRNA was expressed in adult rat submandibular glands but not in the SCA-9 cell line. Determination of cyclic DNA (cDNA) sequence established identity with the coding regions of rat pancreatic pre-proglucagon gene. In conclusion, these results strongly support the idea that rat submandibular glands could represent a source of extrapancreatic glucagon or of its precursor's peptide.

[Epidermal growth factor: a probable oral and digestive health protector]. / Le facteur de croissance épidermique: un gardien potentiel de la santé oro-digestive.

The integrity of oral and digestive mucosa depend on many salivary components like the Epidermal Growth Factor (EGF). Sometimes indicative, sometimes stimulated or modulated factor of oral and digestive health, EGF appears as a clinical marker in neoplastic and inflammatory diseases. As cellular growth factor, it protects the digestive mucosa with stimulation of mucus production and with inhibition of gastric secretion. Equally implicated in healing process, it enhances this one, and determines, in patients, more or less sensibility to inflammatory damages. Its strategic place in various pathologies, as stomach ulcer and tumoral process, open research prospects with a real potential of repair and pronostic.

Preproinsulin I and II mRNA expression in adult rat submandibular glands.

Mammalian salivary glands are known to produce a number of biologically active peptides. The aim of this study was to extend our previous results showing the presence of a biologically active insulin-like immunoreactive peptide in rat salivary glands. In rodents, where two nonallelic and functional insulin genes are expressed, the co-expression of both genes seems to be limited to beta-cells of pancreatic islets or to embryologic developmental processes. We have investigated the expression of insulin genes in rat submandibular glands and in a murine immortalized submandibular cell line, SCA-9. For this purpose, total RNAs were isolated and submitted to reverse transcription. The cDNAs obtained were amplified by a nested polymerase chain reaction using rat preproinsulin I and II primers. Our data show that both preproinsulin I and II mRNAs are expressed in adult rat submandibular glands as well as in the SCA-9 cell line. The identification of salivary gland rat preproinsulin I and II was confirmed by direct sequencing. These results provide, for the first time, evidence for the expression of both preproinsulin I and II mRNA in an extra-pancreatic tissue from adult rodents.

Cultured tumor cells of murine submandibular gland origin: a model to investigate pHi regulation of salivary cells.

Intracellular pH (pHi) and several ion transport mechanisms in cultured murine salivary gland cells (SCA-9) were studied using a videomicrofluorometric method and the H+-specific probe C-SNARF-1. The aim of this study was to test SCA-9 cells' pHi regulation mechanisms and evaluate if this cell line is representative of submandibular gland cells. Resting pHi in unstimulated cells was estimated to be 7.17+/-0.07. To investigate the presence of Na+/H+ and Cl-/HCO3- antiports as well as Na+/K+/2Cl- symports in SCA-9 cells, we used different specific blockers, dimethyl-amiloride, disulfonic stilbene, bumetanide and furosemide. In order to study SCA-9 cell capacity to regulate their pHi in response to alkaline and acid loads, we applied the NH4Cl prepulse method to all these blockers. The results showed that SCA-9 cells possess both antiports and symports involved in pHi regulation, and that this cell line can be used as a convenient model to study pHi regulatory mechanisms in salivary cells.

Vanadyl treatment normalizes submandibular salivary gland insulin-like immunoreactivity in streptozotocin-diabetic rats.

Rat submandibular salivary glands (SSG) contain a compound displaying insulin-like immunoreactivity (ILI) and various biological activities of insulin. As SSG ILI levels were reported to be increased in streptozotocin (STZ)-induced diabetes but not normalized by a two-week insulin treatment, we decided to check whether another antidiabetic treatment, vanadyl sulphate (VOSO4), was able to regulate SSG ILI concentration. A short term (8 days) i.p. VOSO4 treatment (total dose = 1.3 mmol/kg) of rats made diabetic 8 days earlier by a single i.v. injection of STZ (60 mg/kg BW) was able to induce a long-term (4 weeks) correction of hyperglycemia while weight gain was re-established. In untreated diabetic animals (approximately -25%) and increased (approximately +175%) as compared to normal rats. Both parameters were normalized in VOSO4-treated diabetic rats.

Age-dependent changes in insulin-like immunoreactivity in rat submandibular salivary glands.

In recent years, a growing interest had arisen in hormonal factors in salivary glands. We have investigated the changes in the content of an insulin-like immunoreactive (ILI) compound in the submandibular salivary glands of Sprague Dawley rats during physiological aging, in the range 15 days-27 months. The amount of ILI in the submandibular glands of young adult rats was found to be doubled in the post-natal period until the age of puberty and was maintained in senescence. No significant correlation was found between age-dependent variations in ILI levels of submandibular salivary glands and circulating insulin concentrations, further supporting previous indications that ILI is being synthesized in situ. It is possible that ILI could exert paracrine effects within the glands, as regards the development of other glandular structures during the first months of life, as well as the preservation of glandular function in senescent animals as well.