Reversible lysine modification on proteins by using functionalized boronic acids.

Iminoboronates have been utilized to successfully install azide and alkyne bioorthogonal functions on proteins, which may then be further reacted with their bioorthogonal counterparts. These constructs were also used to add polyethylene glycol (PEG) to insulin, a modification which has been shown to be reversible in the presence of fructose. Finally, iminoboronates were used to assemble a folic acid/paclitaxel small-molecule/drug conjugate in situ with an IC50  value of 20.7 nM against NCI-H460 cancer cells and negligible cytotoxicity against the CRL-1502 noncancer cells.

Effects of hyperleptinemia in rat saliva composition, histology and ultrastructure of the major salivary glands.

OBJECTIVE: To study the effect of the satiety hormone, leptin, in saliva proteome and salivary gland histology and ultrastructure. DESIGN: Increases in blood leptin levels were induced through mini-pump infusion in male Wistar rats, during a period of 7 days. Saliva was collected before and at the end of the experimental period, for proteomic analysis, and major salivary glands were collected, at the end, for biochemical, histological and ultrastructural analysis. RESULTS: Immunohistochemistry revealed the presence of leptin receptors in major salivary glands. Salivary amylase levels and enzymatic activity were decreased in saliva, whereas the enzymatic activity of this protein was increased in the cytosol of parotid gland cells. Transmission electron microscopy allowed the observation of high number of electron-dense granules in cytosol of parotid acinar cells, from leptin treated animals. CONCLUSIONS: Increased levels of plasmatic leptin result in changes in saliva composition and salivary glands function. To our knowledge, this is the first study providing evidences for a potential role of leptin in salivary gland secretion and saliva composition. An understanding of how appetite/satiety factors influence saliva composition and how this composition influences food processing in mouth may be relevant in understanding ingestivebehaviour.

α-Synuclein aggregation in the saliva of familial transthyretin amyloidosis: a potential biomarker.

Familial transthyretin amyloidosis (ATTR) is an autosomal dominant disease characterized by the formation of transthyretin (TTR) amyloid deposits. This crippling and fatal disease is associated with point mutations in TTR, a protein mainly produced in the liver. Hence, liver transplantation is the only treatment capable of halting disease progression. Ideally, liver transplantation should be performed as early as possible in the disease course before significant neurologic disability has been incurred. Early detection of disease before serious pathological lesions occur is crucial for the clinical management of patients and for morbidity delay. Unfortunately, the presence of TTR mutations by itself is not a predictor of disease onset or progression. In the present work, we observed an increased oligomerization of α-synuclein in the saliva of ATTR symptomatic individuals comparatively to asymptomatic carriers of the same TTR mutation and healthy control subjects. Based on this observation, we propose monitoring α-synuclein oligomers in saliva as a biomarker of ATTR progression. Since α-synuclein plays a major role in several neurodegenerative disorders, assessing its oligomerization state in this fluid provides a non-invasive approach to survey these pathologies.

A non-invasive method based on saliva to characterize transthyretin in familial amyloidotic polyneuropathy patients using FT-ICR high-resolution MS.

PURPOSE: To identify, characterize and perform a relative quantification of human transthyretin (TTR) variants in human saliva. EXPERIMENTAL DESIGN: Serum and saliva samples were collected from healthy and familial amyloidotic polyneuropathy (FAP) patients, proteins separated by SDS-PAGE, TTR bands excised, in-gel digested and analyzed by MALDI-FTICR. RESULTS: We identified and performed a relative quantification of mutated and native TTR forms in human saliva, based on FTICR-MS. The results are quantitatively identical to the ones obtained with human serum. In FAP patients subjected to cadaveric liver transplant, the TTR mutant form is no longer detected in saliva, while in patients receiving a domino liver from a FAP donor the mutant form of TTR becomes detectable in saliva, thus demonstrating the serum origin of TTR in saliva. CONCLUSIONS AND CLINICAL RELEVANCE: Saliva TTR originates in serum and the ratio of mutant to native TTR is preserved. The method provides a non-invasive detection of mutated TTR and a relative quantification of TTR forms. Diagnostic and disease prognosis of FAP is crucial at early stages of the disease and after liver transplantation, the only curative therapy. A suitable non-invasive method was developed for monitoring the most important FAP biomarker in human saliva.

Analysis of the association between lactotransferrin (LTF) gene polymorphism and dental caries.

OBJECTIVE: The present study evaluated the association between lactotransferrin (LTF) gene polymorphism (exon 2, A/G, Lys/Arg) and dental caries. MATERIAL AND METHODS: A convenience sample of 110 individuals, 12 years old, was divided into: group 1, 48 individuals without caries experience (DMFT=0), and group 2, 62 subjects with caries experience (DMFT>or=1). DNA was obtained from a mouthwash with 3% glucose solution, followed by a scrapping of the oral mucosa. After DNA purification, polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) was performed to access the study polymorphism. The LTF A/G (Lys/Arg) polymorphism had been previously reported as located in exon 1. RESULTS: Allele 1 of the study polymorphism was associated with low DMFT index and showed a protective effect against caries experience (OR=0.16, IC=0.03-0.76, p=0.01). CONCLUSIONS: Lactotransferrin A/G (exon 2, Lys/Arg) polymorphism was associated with susceptibility to dental caries in 12-year-old students.