Identification of Lys-Pro-Gln as a Novel Cleavage Site Specificity of Saliva-associated Proteases

Helmerhorst, Eva J.; Sun, Xiuli; Salih, Erdjan; Oppenheim, Frank G.

doi:10.1074/jbc.m708282200

Cited by 62 publications

(71 citation statements)

References 44 publications

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“…Indeed, we did not find any significant difference in salivary concentration of PRP-1 type proteins and PRP-3 type proteins between diabetics and controls. Fragmentation of P-C peptide, occurring mainly at the XPQ2G site (where X is preferably K, but often S and R), seems to be related to a glutamine endoprotease activity probably of microbial origin, as reported by Helmerhorst et al (27). Our data suggest that in the oral environment of diabetic subjects the activity of this proteolytic enzyme could be higher Elution ranges of the principal classes of human salivary proteins/peptides are indicated.…”

Section: Discussionsupporting

confidence: 50%

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Alterations of the Salivary Secretory Peptidome Profile in Children Affected by Type 1 Diabetes

Cabras

Pisano

Mastinu

et al. 2010

Molecular & Cellular Proteomics

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The acidic soluble fraction of whole saliva of type 1 diabetic children was analyzed by reversed phase (RP) 1 -HPLC-ESI-MS and compared with that of sex-and age-matched control subjects. Salivary acidic proline-rich phosphoproteins (aPRP), histatins, ␣-defensins, salivary cystatins, statherin, proline-rich peptide P-B (P-B), betathymosins, S100A8 and S100A9*(S100A9* corresponds to S100A9 vairant lacking the first four amino acids), as well some naturally occurring peptides derived from salivary acidic proline-rich phosphoproteins, histatins, statherin, and P-B peptide, were detected and quantified on the basis of the extracted ion current peak area. The level of phosphorylation of salivary acidic proline-rich phosphoproteins, histatin-1 (Hst-1), statherin and S100A9* and the percentage of truncated forms of salivary acidic proline-rich phosphoproteins was also determined in the two groups. The study revealed that statherin, proline-rich peptide P-B, P-C peptide, and histatins, were significantly less concentrated in saliva of diabetic subjects than in controls, while concentration of ␣-defensins 1, 2 and 4 and S100A9* was higher. The low concentration of P-C peptide was paralleled by high levels of some of its fragments. On the whole, the study highlighted the severe impairment of the repertoire of peptides involved in the safeguard of the oral cavity in children who have diabetes, as well as an higher concentration of the proinflammatory mediator S100A9* with respect to healthy children. Molecular & Cellular Proteomics 9:2099 -2108, 2010.Type 1 diabetes mellitus is a disease with universal distribution, affecting all populations (1) with an incidence increasing in Europe (2). Because type 1 diabetes involves many organs and tissues, signs and symptoms of diabetes can occur in the oral cavity. Indeed, several studies have shown that the prevalence, severity, and progression of periodontal diseases are significantly increased in diabetics, and the pathology is considered an important risk factor for periodontitis (3). The study of Lalla et al. (4) showed an association between diabetes and the increased risk for periodontal destruction even very early in life. Flow rate and composition of saliva are crucial for the maintenance of oral cavity health, and both have been found altered in diabetic subjects, although with contradictory findings. For instance, several studies reported a reduced resting salivary flow rate in adults and children who have type 1 diabetes with respect to healthy subjects (5-10), but it was also observed that stimulated saliva of diabetics and controls did not significantly differ (11,12). Total protein concentration of saliva was found either increased or not affected by the diabetic status. Lopez et al. (9) reported higher urea and total protein salivary content in diabetic children than in controls. Conversely, a study on 35 adult insulin-dependent diabetics demonstrated that they did not show a decreased saliva concentration of several innate antimicrobial factors (lysozyme, lactoferri...

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Section: Discussionsupporting

confidence: 50%

“…Fragments 1-14, 1-25, 5-25, 26 -35, 26 -44, and 36 -44 of P-C peptide have been already detected in saliva from healthy subjects (27). An association of fragments 1-14 and 26 -44 to high numbers of dental caries and the presence of fragment 1-14 in saliva of subjects affected by Sjogrens syndrome were also reported (28).…”

Section: Discussionmentioning

confidence: 91%

Alterations of the Salivary Secretory Peptidome Profile in Children Affected by Type 1 Diabetes

Cabras

Pisano

Mastinu

et al. 2010

Molecular & Cellular Proteomics

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“…Endoprotease activity with glutamine specificity could result in hydrolysis of the Q 6 ÀC 7 peptide bond to produce Manse-AS [1][2][3][4][5][6] . There is currently no evidence for these enzymes in insects, although they have been found to be present in human saliva (Helmerhorst et al, 2008) and in germinating barley seeds (Davy et al, 1998).…”

Section: Discussionmentioning

confidence: 98%

Effects of Manduca sexta allatostatin and an analogue on the peach‐potato aphid Myzus persicae (hemiptera: aphididae) and degradation by enzymes in the aphid gut

Matthews¹,

Down²,

Audsley³

2010

Arch Insect Biochem Physiol

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The oral toxicity of the C-type allatostatin, Manduca sexta allatostatin (Manse-AS) and the analogue δR³δR⁵Manse-AS, where R residues were replaced by their D-isomers, were tested against the peach-potato aphid Myzus persicae by incorporation into an artificial diet. Both peptides had significant dose-dependent effects on mortality, growth, and fecundity compared with control insects. The analogue, δR³δR⁵Manse-AS, had an estimated LC₅₀ of 0.31 µg/µl diet and was more potent than Manse-AS (estimated LC₅₀ of 0.58 µg/µl diet). At a dose of 0.35 µg δR³δR⁵Manse-AS/µl diet, 76% of the aphids were dead after 6 days and all were dead after 10 days. In comparison, three times the dose of Manse-AS was required to achieve 74% mortality after 8 days and 98% mortality after 16 days. The degradation of both peptides by extracts prepared from the gut of M. persicae was investigated. The estimated half-life of Manse-AS, when incubated with the gut extract from M. persicae, was 31 min. Degradation was due to a cathepsin L-like cysteine protease, carboxypeptidase-like activity, endoprotease activity with glutamine specificity, pyroglutamate aminopeptidase activity, and possibly trypsin-like proteases. The half-life of the δR³δR⁵ Manse-AS analogue was enhanced (73 min) with the D-isomers of R appearing to prevent cleavage around the R residues by cathepsin L-like cysteine proteases or from trypsin-like proteases. The greater stability of the analogue may explain its increased potency in M. persicae. This work demonstrates the potential use of Manse-AS and analogues, with greater resistance to enzymatic attack, in aphid control strategies.

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“…PRPs are posttranslationally modified within the gland and furthermore undergo excessive degradation after secretion in the oral cavity by microbial proteases (16, 37). As a result, human saliva contains a diverse mixture of acidic and basic PRP-derived proteins and peptides (17,20,21).It has been hypothesized that structural mimicry between gluten and other proteins may be a factor in the etiology of CD. Kagnoff and coworkers (23) noted earlier structural similarities between a 12-amino acid residue peptide from E1b protein from adenovirus and ␣-gliadin.…”

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confidence: 99%

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confidence: 99%

Despite sequence homologies to gluten, salivary proline-rich proteins do not elicit immune responses central to the pathogenesis of celiac disease

Tian

Leffler

Kelly

et al. 2015

American Journal of Physiology-Gastrointestinal and Liver Physi

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Helmerhorst EJ. Despite sequence homologies to gluten, salivary proline-rich proteins do not elicit immune responses central to the pathogenesis of celiac disease. Am J Physiol Gastrointest Liver Physiol 309: G910 -G917, 2015. First published October 1, 2015; doi:10.1152/ajpgi.00157.2015.-Celiac disease (CD) is an inflammatory disorder triggered by ingested gluten, causing immunemediated damage to the small-intestinal mucosa. Gluten proteins are strikingly similar in amino acid composition and sequence to prolinerich proteins (PRPs) in human saliva. On the basis of this feature and their shared destination in the gastrointestinal tract, we hypothesized that salivary PRPs may modulate gluten-mediated immune responses in CD. Parotid salivary secretions were collected from CD patients, refractory CD patients, non-CD patients with functional gastrointestinal complaints, and healthy controls. Structural similarities of PRPs with gluten were probed with anti-gliadin antibodies. Immune responses to PRPs were investigated toward CD patient-derived peripheral blood mononuclear cells and in a humanized transgenic HLA-DQ2/DQ8 mouse model for CD. Anti-gliadin antibodies weakly cross-reacted with the abundant salivary amylase but not with PRPs. Likewise, the R5 antibody, recognizing potential antigenic gluten epitopes, showed negligible reactivity to salivary proteins from all groups. Inflammatory responses in peripheral blood mononuclear cells were provoked by gliadins whereas responses to PRPs were similar to control levels, and PRPs did not compete with gliadins in immune stimulation. In vivo, PRP peptides were well tolerated and nonimmunogenic in the transgenic HLA-DQ2/DQ8 mouse model. Collectively, although structurally similar to dietary gluten, salivary PRPs were nonimmunogenic in CD patients and in a transgenic HLA-DQ2/DQ8 mouse model for CD. It is possible that salivary PRPs play a role in tolerance induction to gluten early in life. Deciphering the structural basis for the lack of immunogenicity of salivary PRPs may further our understanding of the toxicity of gluten. celiac disease; immune response; salivary protein; gluten; mouse model CELIAC DISEASE (CD) is a T cell-mediated inflammatory enteropathy that manifests itself in genetically predisposed individuals. In its etiology, both genetic and environmental factors are implicated. The major genetic risk factors are carriage of HLA-DQ2 heterodimers, expressed in 90 -95% of CD patients, or HLA-DQ8 heterodimers, expressed in the remainder of CD patients. The primary environmental cause of CD is ingested gluten, a heterogeneous mixture of glutamine-and proline-rich storage proteins present in wheat, rye, and barley (10,12,22,46). According to solubility in alcoholic solutions, gluten is divided into soluble gliadins and insoluble glutenins. Gluten proteins are unusual because they have a high content of proline (P) and glutamine (Q). In the most abundant gliadins, Q comprises 35-38% of the total amino acids, while P ranges from 13-17% (49, 62, 63). The high P conten...

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Identification of Lys-Pro-Gln as a Novel Cleavage Site Specificity of Saliva-associated Proteases

Cited by 62 publications

References 44 publications

Alterations of the Salivary Secretory Peptidome Profile in Children Affected by Type 1 Diabetes

Alterations of the Salivary Secretory Peptidome Profile in Children Affected by Type 1 Diabetes

Effects of Manduca sexta allatostatin and an analogue on the peach‐potato aphid Myzus persicae (hemiptera: aphididae) and degradation by enzymes in the aphid gut

Despite sequence homologies to gluten, salivary proline-rich proteins do not elicit immune responses central to the pathogenesis of celiac disease

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