S100A1
Protein S100-A1 (S-100 protein alpha chain) (S-100 protein subunit alpha) (S100 calcium-binding protein A1) [S100A]
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We used an in vitro model to evaluate the effects of cellular aging and inflammation on the gene expression and protein secretion profiles of adipocytes. 3T3-L1 mouse preadipocytes were cultured according to standard conditions and analyzed at different time points both at the basal state and after an acute stimulation with LPS. The mRNA levels of CCAAT/enhancer-binding protein (C/EBP)alpha, peroxisome proliferator-activated receptor (PPAR)gamma and S100A1 were maximal during adipocyte differentiation and then significantly decreased. The expression of the GLUT4 and IRS-1 genes peaked during differentiation and then decreased in aged cells. The mRNA levels and secretion of adiponectin, quickly rose as adipocytes matured and then declined. The mRNA levels of IL6, as well as its secretion, increased as preadipocytes matured and became old cells; a similar trend was also found for MCP-1. LPS decreased the mRNA levels of C/EBPalpha and PPARgamma at all time points, as well as those of GLUT4, IRS-1 and adiponectin. LPS significantly increased the mRNA levels of IL-6, as well as its secretion, with a similar trend also observed for MCP-1. These data suggest that aging adipocytes in vitro show a decline in pro-adipogenic signals, in genes involved in glucose metabolism and cytoskeleton maintenance and in adiponectin. These changes are paralleled by an increase in inflammatory cytokines; inflammation seems to mimic and amplify the effects of cellular aging on adipocytes.
MeSH Terms
- 3T3-L1 Cells
- Adipocytes
- Aging
- Animals
- Cytokines
- Gene Expression Regulation
- Immunologic Factors
- Inflammation
- Mice
This article presents new information regarding the complement/level of S100 family members expressed in the brain and reviews the contribution of brain S100 family members to nervous system function and disease. A total of ten S100 family members are reported in the literature to be expressed in brain -S100A1, S100A2, S100A4, S100A5, S100A6, [[S100A10]], S100A11, [[S100A13]], S100B, and S100Z. Quantitative Northern blot analysis detected no S100A3, S100A8, S100A9 or S100A14 mRNA in mouse brain suggesting that these family members are not expressed in the brain. In addition, there was a 100-fold range in the mRNA levels for the six family members that were detected in mouse brain: S100A1/S100B levels were 5-fold higher than S100A6/[[S100A10]] levels and 100-fold higher than S100A4/[[S100A13]] levels. Five of these six family members (S1100A1, S100A6, [[S100A10]], [[S100A13]], and S100B) exhibited age-dependent increases in expression in adult mice that ranged from 5- to 20-fold. Although previous studies on S100 function in the nervous system have focused on S100B, other family members (S100A1, S100A3, S100A4, S100A5) have been implicated in neurological diseases. Like S100B, intra- and inter-cellular forms of these family members have been linked to cell growth, cell differentiation, and apoptotic pathways. Studies presented here demonstrate that ablation of S100A1 expression in PC12 cells results in increased resistance to Abeta peptide induced cell death, stabilization of intracellular [Ca2 ] homeostasis, and reduced amyloid precursor protein expression. Altogether, these results confirm that S100-mediated signal transduction pathways play an important role in nervous system function/disease and implicate S100A1 in the neuronal cell dysfunction/death that occurs in Alzheimer's disease.
MeSH Terms
- Aging
- Alzheimer Disease
- Amyloid beta-Peptides
- Amyloid beta-Protein Precursor
- Animals
- Apoptosis
- Brain Chemistry
- Calcium
- Cell Differentiation
- Cell Line
- Cell Proliferation
- Gene Expression Regulation
- Homeostasis
- Mice
- Mice, Inbred C57BL
- Nervous System Diseases
- Nervous System Physiological Phenomena
- Neurons
- Peptide Fragments
- S100 Proteins
- Signal Transduction
Ca(2 ) signaling plays a central role in cardiac contractility and adaptation to increased hemodynamic demand. We have generated mice with a targeted deletion of the S100A1 gene coding for the major cardiac isoform of the large multigenic S100 family of EF hand Ca(2 )-binding proteins. S100A1(-/-) mice have normal cardiac function under baseline conditions but have significantly reduced contraction rate and relaxation rate responses to beta-adrenergic stimulation that are associated with a reduced Ca(2 ) sensitivity. In S100A1(-/-) mice, basal left-ventricular contractility deteriorated following 3-week pressure overload by thoracic aorta constriction despite a normal adaptive hypertrophy. Surprisingly, heterozygotes also had an impaired response to acute beta-adrenergic stimulation but maintained normal contractility in response to chronic pressure overload that coincided with S100A1 upregulation to wild-type levels. In contrast to other genetic models with impaired cardiac contractility, loss of S100A1 did not lead to cardiac hypertrophy or dilation in aged mice. The data demonstrate that high S100A1 protein levels are essential for the cardiac reserve and adaptation to acute and chronic hemodynamic stress in vivo.
MeSH Terms
- Adrenergic beta-Agonists
- Aging
- Animals
- Calcium Signaling
- Calcium-Binding Proteins
- Gene Targeting
- Heart Ventricles
- Hemodynamics
- Heterozygote
- Isoproterenol
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Myocardial Contraction
- Receptors, Adrenergic, beta
- S100 Proteins
- Stress, Physiological
- Ventricular Function
Annexins and S100 proteins constitute two multigenic families of Ca2 -modulated proteins that have been implicated in the regulation of both intracellular and extracellular activities. Some annexins can interact with certain S100 protein dimers thereby forming heterotetramers in which an S100 dimer crosslinks two copies of the partner annexin. It is suggested that S100 protein binding to an annexin might serve the function of regulating annexin function and annexin binding to an S100 protein might regulate S100 function. In the present study, annexin V, annexin VI (or ANXA5 and ANXA6, respectively, according to a novel nomenclature), S100A1 and S100B were analyzed for their subcellular localization in developing and adult avian skeletal muscles by confocal laser scanning microscopy, immunogold cytochemistry, and western blotting, and for their ability to form annexin-S100 heterocomplex in vivo by immunoprecipitation. These four proteins displayed distinct expression patterns, ANXA5 being the first to be expressed in myotubes (i.e. at embryonic day 8), followed by ANXA6 (at embryonic day 12) and S100A1 and S100B (between embryonic day 12 and embryonic day 15). The two annexins and the two S100 proteins were found associated to different extents with the sarcolemma, membranes of the sarcoplasmic reticulum, and putative transverse tubules where they appeared to be co-localized from embryonic day 18 onwards. No one of these proteins was found associated with the contractile apparatus of the sarcomeres. Immunoprecipitation studies indicated that ANXA6/S100A1 and ANXA6/S100B complexes formed in vivo. Whereas, ANXA5 was not recovered in S100A1 or S100B immunoprecipitates. From our data we suggest that: (i) ANXA5 and ANXA6, and S100A1 and S100B can be used as markers of skeletal muscle development; (ii) ANXA6 and S100A1 and S100B appear strategically located close to or on skeletal muscle membrane organelles that are critically involved in the regulation of Ca2 fluxes, thus supporting previous in vitro observations implicating S100A1 and ANXA6 in the stimulation of Ca2 -induced Ca2 release; and (iii) ANXA6/S100A1 and ANXA6/S100B complexes can form in vivo thereby regulating each other activities and/or acting in concert to regulate membrane-associated activities.
MeSH Terms
- Aging
- Animals
- Annexin A5
- Annexin A6
- Calcium Signaling
- Calcium-Binding Proteins
- Cell Differentiation
- Chick Embryo
- Chickens
- Gene Expression Regulation, Developmental
- Immunohistochemistry
- Intracellular Membranes
- Microscopy, Confocal
- Microscopy, Electron
- Muscle Fibers, Skeletal
- Muscle, Skeletal
- Nerve Growth Factors
- S100 Calcium Binding Protein beta Subunit
- S100 Proteins
- Subcellular Fractions
Corpora amylacea (C.A.) also named polyglucosan bodies (P.B.) are one of the hallmarks of normal brain aging. Although their functions are not yet clear, C.A. increase in number in patients suffering from neurodegenerative diseases. C.A. contain 88% of hexoses and 4% of proteins. Most of the proteins in C.A. are aging or stress proteins such as heat shock proteins, ubiquitinated proteins and advanced glycation end products which are also proinflammatory products. Stimulated by the potential role played by some S100 proteins in the inflammatory process which may be triggered in C.A., we investigated, by immunohistochemistry, the presence of different S100 proteins (S100A1, S100A2, S100A3, S100A4, S100A5, S100A6, S100A8, S100A9, [[S100A12]] and S100B) in C.A. from normal human brain. Among the ten S100 proteins analyzed, nine (S100A) were detected in C.A. Three S100 proteins (S100A8, S100A9, [[S100A12]]) which are highly expressed in activated macrophages and used as inflammatory markers were detected in C.A. S100A8 was, in addition, found in thick neuronal processes from the pons. One (S100B) could not be found in C.A. although it was highly expressed in astrocytes. In C.A., the staining intensity was estimated by computer-assisted microscopy and gave the following order: S100A1 congruent withS100A8 congruent with S100A9>S100A5> or =S100A4>[[S100A12]]>S100A6> S100A2=S100A3. The potential inflammatory role played by S100 proteins in C.A. is discussed.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- Antibody Specificity
- Female
- Humans
- Inclusion Bodies
- Male
- Middle Aged
- Neurodegenerative Diseases
- Pons
- Reference Values
- S100 Proteins