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Results for “Lithostathine”

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PubMed1992

Neuronal thread protein over-expression in brains with Alzheimer's disease lesions.

Neuronal thread protein (NTP) is a recently characterized molecule that is over-expressed in brains with Alzheimer's disease (AD) lesions. The present study encompasses a detailed analysis of NTP expression in AD compared with other neurodegenerative diseases and aged controls. Using a specific monoclonal antibody, NTP immunoreactivity was evaluated in 309 paraffin-embedded sections from 8 different regions of the frontal, parietal, and temporal lobes of 73 brains with AD, AD + Down's syndrome (DN), AD + Parkinson's disease (PD), PD dementia (PDD), aged controls, and disease controls with Huntington's disease, multi-infarct dementia, or schizophrenia. In 250 adjacent blocks of snap-frozen unfixed tissue the concentration of NTP (ng/mg of protein) was measured using a 3-site forward sandwich monoclonal antibody based immunoradiometric assay (M-IRMA). Immunohistochemical studies demonstrated that brains with AD, AD + PD, and AD + DN contained significantly higher densities of NTP immunoreactive neurons and more frequent immunostaining of neuropil and white matter fibers compared with PDD and aged controls (both P < 0.001) which had few or no AD lesions. In addition, the overall mean concentrations of NTP in AD, AD + PD, and AD + DN were significantly higher than in PDD and aged controls (P < 0.005). Greater degrees of NTP immunoreactivity and higher concentrations of the protein in cerebral tissue were significantly correlated with AD diagnosis and abundant neurofibrillary tangles (P < 0.005). The findings suggest that NTP over-expression may serve as a marker for the type of neuronal degeneration that occurs in AD.

Aged↗
PubMed1996

Modulation of neuronal thread protein expression with neuritic sprouting: relevance to Alzheimer's disease.

Widespread proliferation of dystrophic neurites in the cerebral cortex represents an important neuroanatomical correlate of dementia in Alzheimer's disease (AD). Increased CNS expression of the 21-kDa neuronal thread protein (NTP) species is also correlated with dementia in AD. Pilot in vitro experiments provided evidence that high-level NTP expression might be linked to neuritic growth. The present study examines retinoic acid (RA) modulation of NTP expression during neurite outgrowth and neuronal differentiation in SH-Sy5y neuroblastoma and PNET2 CNS-derived cells. In both cell lines, RA-induced neuronal differentiation resulted in increased synthesis, expression, and phosphorylation of several NTP species, with high steady-state levels and stepwise hyper-phosphorylation of 21-kDa NTP molecules. With neurite outgrowth, NTP molecules were translocated from the perikarya to long, slender, unbranched cell processes (axons) and growth cones. RA-mediated changes in NTP expression were independent of DNA synthesis. The findings suggest that high-level expression of 21-kDa, and closely related phosphorylated NTP molecules correlates with neuritic growth. Therefore, over-expression of 21-kDa NTP molecules in AD probably reflects the widespread cortical neuritic sprouting associated with dementia. In view of the rapid phosphorylation and cell process translocation of NTP that occurs during neurite outgrowth in vitro, the accumulation of NTP in AD cortical neuronal perikarya suggests a further problem related to post-translational processing and transport of NTP molecules in AD neurodegeneration.

Alzheimer Disease↗
PubMed1994

Isolation, structural determination and expression of a novel reg gene, human regI beta.

We have isolated a novel human gene and cDNA encoding a member of the regI proteins, regI beta. The gene encodes a 166-amino acid protein which has 22 amino acid substitutions in comparison with the previously isolated human reg protein, regI alpha. RegI beta was expressed only in pancreas, whereas regI alpha was expressed in kidney and stomach as well as in pancreas.

Amino Acid Sequence↗
PubMed1994

Characterization of the 5'-regulatory region of rat Reg I gene.

We report here the characterization of the 5'-regulatory region of rat Reg I gene encoding a growth stimulating factor for pancreatic beta-cells. Transient expression assays of the 5'-flanking region/luciferase fusion gene in AR4-2J cells showed that the -304/-237 region contained positive cis-acting elements. Gel shift assays using AR4-2J and rat pancreas nuclear extracts showed the formation of a specific complex with the -256/-237 oligonucleotide.

Animals↗
PubMed1989

N-terminal sequence extension in the glycosylated forms of human pancreatic stone protein. The 5-oxoproline N-terminal chain is O-glycosylated on the 5th amino acid residue.

The pancreatic stone protein isolated from human calculi (PSP) derives from the immunoreactive protein forms detected in human pancreatic juice (PSP S2-5) through the tryptic cleavage of the Arg-11-Ile-12 bond. Among the eleven amino acids of the PSP S2-5 N-terminal extension Z-E-A-Q-T-E-L-P-Q-A-R, the first residue is an oxoproline and the fifth, a threonine, bears the single carbohydrate chain of the protein molecules. Variations in the glycan chain composition account for the differences in the Mr of PSP S2-5. The PSP S2-5 forms are very soluble in aqueous solutions between the pH values 5.0-9.0, whereas the proteolysated form is scarcely soluble.

Acetylgalactosamine↗
PubMed1988

The human pancreatic stone protein.

Chronic calcifying pancreatitis (CCP) is characterized by the presence of stones in pancreatic ducts. Calcium carbonate (CaCO3) is the main constituent of stones, to which is associated an organic matrix consisting primarily of one protein of Mr 14,000, the pancreatic stone protein or PSP. PSP is not present as such in pancreatic juice, but in polymorphic forms with higher molecular weights. These secretory forms (PSP S2-5, Mr 16-19,000) are synthesized in the acinar cells of the pancreas and secreted along the same secretory pathway as the exocrine enzymes. The heterogeneity of the forms of higher Mr (PSP S2-5) is probably due to different glycosylation patterns. PSP and PSP S1 are generated by the cleavage of an Arg-Ile bond in the N-terminal part of PSP S2-5. The N-terminal sequence of PSP (40 amino acids) is identical to that of PSP S1, whose complete sequence (133 amino acids) has been determined. Yet, the two proteins differ by their pI. Pancreatic juice is normally supersaturated in CaCO3, suggesting the presence of a stabilizer preventing CaCO3 precipitation. The PSP S could play that role, since an activity inhibiting the nucleation and growth in vitro of CaCO3 crystals was found in pancreatic juice, associated with these proteins. Moreover, PSP S concentration was significantly lower in the pancreatic juice of patients with CCP than in control patients. Proteins homologous to PSP S were also found in the dog, rat, swine, monkey and ox. They constitute a new family of pancreatic secretory proteins, whose biological role would be to maintain pancreatic juice in a stable state towards CaCO3.

Amino Acid Sequence↗
PubMed1989

Characterization in rat pancreatic juice of a protein homologous to the human pancreatic stone protein.

1. The pancreatic stone protein (PSP, Mr 15,000) which has been discovered in human calculi derives from the native glycosylated forms of the protein (Mrs 17,500-22,000) which are present in human pancreatic juice through tryptic cleavage of the Arg 11-Ile 12 bond. 2. In the present study, a homologous native form of the protein (Mr 17,000) was purified from rat pancreatic juice. 3. Its N-terminal amino acid sequence was found to display a high degree of homology with that of the human native protein forms, apart from the fact that it was not glycosylated. 4. In rat as in human, tryptic cleavage of the Arg 11-Ile 12 bond transforms a soluble protein into one which is practically insoluble at neutral pH.

Amino Acid Sequence↗
PubMed1992

Sequence of a cDNA clone encoding a rat Reg-2 protein.

We report here the nucleotide sequence of a rat cDNA clone encoding a protein homologous to the Reg (regenerating) protein. The encoded protein, designated Reg-2, shows 60%, 78% and 61% similarities with the reported amino acid sequences of the rat, bovine and human proteins, respectively.

Amino Acid Sequence↗
PubMed2005

The multifunctional family of secreted proteins containing a C-type lectin-like domain linked to a short N-terminal peptide.

PSP/Lithostathine/PTP/regI, PAP/p23/HIP, reg1L, regIV and "similar to PAP" are the members of a multifunctional family of secreted proteins containing a C-type lectin-like domain linked to a short N-terminal peptide. The expression of this group of proteins is controlled by complex mechanisms, some members being constitutively expressed in certain tissues while, in others, they require activation by several factors. These members have several apparently unrelated biological effects, depending on the member studied and the target cell. These proteins may act as mitogenic, antiapoptotic or anti-inflammatory factors, can regulate cellular adhesion, promote bacterial aggregation, inhibit CaCO3 crystal growth or increase resistance to antitumoral agents. The presence of specific receptors for these proteins is suggested because biological effects were observed after the addition of purified protein to culture media or after systemic administration to animals, whereas other biological effects could be explained by their biochemical capacity to form homo or heteromers or to form insoluble fibrils at physiological pH.

Amino Acid Sequence↗
PubMed2005

Cyclin D1 activation through ATF-2 in Reg-induced pancreatic beta-cell regeneration.

Regenerating gene product (Reg) is induced in pancreatic beta-cells and acts as an autocrine/paracrine growth factor for regeneration via a cell surface Reg receptor. However, the manner by which Reg induces beta-cell regeneration was unknown. In the present study, we found that Reg increased phospho-ATF-2, which binds to -57 to -52 of the cyclin D1 gene to activate the promoter. The Reg/ATF-2-induced cyclin D1 promoter activation was attenuated by PI(3)K inhibitors such as LY294002 and wortmannin. In Reg knockout mouse islets, the levels of phospho-ATF-2, cyclin D1, and phospho-Rb were greatly decreased. These results indicate that the Reg-Reg receptor system stimulates the PI(3)K/ATF-2/cyclin D1 signaling pathway to induce beta-cell regeneration.

Activating Transcription Factor 2↗
PubMed2005

Exocrine meets endocrine: pancreatic stone protein and regenerating protein--two sides of the same coin.

BACKGROUND: Regenerating protein (reg) and pancreatic stone protein (PSP) have been discovered independently in the fields of diabetes and pancreatitis. MATERIALS AND METHODS: These proteins are identical; however, because of the gap between the endocrine and exocrine field, there was never a consensus and the nomenclature has not been rectified. Since the time of the initial discovery, more isoforms have been unified. Historically, PSP was discovered long before reg, yet, in many areas outside of the pancreatitis research field, reg is being used. RESULTS: For PSP/reg, a role in proliferation and regeneration of islet cells has been postulated. A hitherto insufficiently understood phenomenon is the massive up-regulation of PSP/reg in pancreatic tissue and juice under conditions of stress. Similarly, PAP (pancreatitis-associated protein)/reg III has been attributed various functional roles. Structurally, the ability to form fibrils after tryptic cleavage is a striking common features of both proteins. However, this biochemical transformation is in itself not enough to gain functional insight. Thus, physiological and genetic approaches are required to further characterize the role of these proteins in the pancreas. Recently, more evidence has been presented in support of the theory that PSP/reg plays a key role in islet neogenesis/regeneration. CONCLUSIONS: In this review we discuss the debate on the localization and functional roles of PSP/reg and PAP/regIII. Therefore, we have summarized hypotheses and experimental results supporting such hypotheses.

Animals↗
PubMed2024

Identification of biomarkers and potential therapeutic targets for pancreatic cancer by proteomic analysis in two prospective cohorts.

Pancreatic cancer (PC) is the deadliest malignancy due to late diagnosis. Aberrant alterations in the blood proteome might serve as biomarkers to facilitate early detection of PC. We designed a nested case-control study of incident PC based on a prospective cohort of 38,295 elderly Chinese participants with &#x223c;5.7 years' follow-up. Forty matched case-control pairs passed the quality controls for the proximity extension assay of 1,463 serum proteins. With a lenient threshold of p&#xa0;<&#xa0;0.005, we discovered regenerating family member 1A (REG1A), REG1B, tumor necrosis factor (TNF), and phospholipase A2 group IB (PLA2G1B) in association with incident PC, among which the two REG1 proteins were replicated using the UK Biobank Pharma Proteomics Project, with effect sizes increasing steadily as diagnosis time approaches the baseline. Mendelian randomization analysis further supported the potential causal effects of REG1 proteins on PC. Taken together, circulating REG1A and REG1B are promising biomarkers and potential therapeutic targets for the early detection and prevention of PC.

Humans↗
PubMed1988

Characterization of two glycoproteins of human pancreatic juice: P35, a truncated protease E and P19, precursor of protein X.

Four glycoproteins were separated by SDS-polyacrylamide gel electrophoresis of proteins of human pancreatic juice devoid of free proteolytic activity. The two low molecular weight glycoproteins were isolated and characterized. Protein P19, the precursor family of protein X, was analyzed by its carbohydrate content which seemed to play an important role in protein solubility at pH 8.0. Protein P35 was found to be a Con A-binding protein rich in mannose. Its N-terminal amino acid sequence covering 33 residues revealed a strong homology with human protease E without the dipeptide Val-Val. Is P35 a protein homologous to the subunit III of bovine procarboxypeptidase A?

Amino Acid Sequence↗
PubMed1998

Human pancreatic reg protein immunoenzymatic assay and molecular form in serum.

A direct sandwich immunoassay was developed to quantify the human reg protein, a non enzymatic pancreatic acinar protein the biological function of which remains elusive. Polystyrene balls were coated with specific IgG fraction as the first antibody and horseradish peroxidase labelled IgG was used as a second antibody. The linearity of the assay was good over a concentration range of 1.25-100 ng/ml and the good parallelism obtained between the standard and the assay dilution curves in serum and pancreatic juice indicates the absence of non-specific interfering reactions. Gel filtration of serum showed that the reg protein was eluted in the fractions corresponding to the proteins of around 25 kDa and that the chromatographic behaviour of the serum protein was identical to that of the purified pancreatic protein when added to serum. This assay was simple, specific, sensitive and reproducible and may permit the determination of low levels of reg protein in different biological fluids.

Calcium-Binding Proteins↗
PubMed1997

Specific reg II gene overexpression in the non-obese diabetic mouse pancreas during active diabetogenesis.

The reg gene, previously described in islets of 90% pancreatectomized and nicotinamide-treated rats, has been shown to be expressed in many pharmacological or surgical animal models of beta cell regeneration. We have studied the non-obese diabetic (NOD) mouse, which represents a good model of spontaneous autoimmune diabetes in which regenerative processes have recently been demonstrated. Two reg genes have been described in the mouse genome, both recognized by the human reg cDNA. In a previous work, using the human probe, we have demonstrated a strong correlation between pancreatic reg gene expression and the likelihood of developing diabetes. In the present study, we have examined the respective levels of both mouse reg I and reg II mRNA in the NOD mouse pancreas using their specific cDNA probes. We found that reg II expression was specifically prevalent compared to reg I, irrespective of sex or state of the disease. Reg II mRNA was particularly increased in overtly diabetic female mice and in cyclophosphamide-treated male mice. These data underline the need to study separately the reg genes using specific probes and show that both reg genes are subjected to various regulations, strongly suggesting that their physiological functions may be different.

Animals↗
PubMed1999

Mutations of RegIalpha are associated with enterochromaffin-like cell tumor development in patients with hypergastrinemia.

BACKGROUND & AIMS: The RegIalpha gene (Reg) encodes a secretory protein proposed to regulate islet beta-cell and gastric mucous cell growth. Reg is expressed in rat gastric enterochromaffin-like (ECL) cells. The aim of this study was to examine Reg expression in human corpus and to determine the identity of Reg in ECL cell carcinoid tumors in hypergastrinemic patients. METHODS: Reg messenger RNA (mRNA) abundance was quantified by Northern blot in extracts of gastric corpus from patients with and without ECL cell tumors and in AR4-2J cells stimulated by gastrin; cellular origins were determined by immunocytochemistry. Mutations of Reg were determined by reverse-transcription polymerase chain reaction, cloning, and sequencing, and the mutated protein was expressed in HIT-T15 cells. RESULTS: Reg mRNA abundance was increased approximately threefold in the corpus of hypergastrinemic patients compared with controls, and was enriched in 3 of 7 ECL cell carcinoid tumors but not in non-endocrine cell gastric polyps. In AR4-2J cells, gastrin stimulated Reg mRNA abundance; this was eliminated by the gastrin/cholecystokinin B antagonist L-740,093 (10(-9) mol/L). Immunocytochemistry indicated that Reg was located in both chief cells and ECL cells in human corpus. Mutations of Reg were identified in 3 of 5 patients with ECL cell carcinoid tumors; in 2 cases, mutation of the initiator methionine residue led to exclusion of the protein from the secretory pathway. CONCLUSIONS: Gastrin regulates Reg mRNA abundance in human corpus. Mutations of Reg that prevent secretion are associated with ECL cell carcinoids, suggesting a function as an autocrine or paracrine tumor suppressor.

Adult↗