Transient response of serpinA3 during cellular stress.

We demonstrated that serpinA3c/k relocates from the cytoplasm to the apical tubular membrane (ATM) in chronic kidney disease (CKD), suggesting its secretion in luminal space in pathophysiological contexts. Here, we studied serpinA3c/k expression and secretion under different stressful conditions in vitro and in vivo. HEK-293 cells were transfected with a FLAG-tagged serpinA3c/k clone and exposed to H2 O2 or starvation. Both stressors induced serpinA3c/k secretion but with a higher molecular weight. Glycanase treatment established that serpinA3c/k is glycosylated. Site-directed mutagenesis for each of the four glycosylation sites was performed. During cellular stress, serpinA3c/k secretion increased with each mutant except in the quadruple mutant. In rats and patients suffering acute kidney injury (AKI), an atypical urinary serpinA3c/k excretion (uSerpinA3c/k) was observed. In rats with AKI, the greater the induced kidney damage, the greater the uSerpinA3 c/k, together with relocation toward ATM. Our findings show that: (1) serpinA3c/k is glycosylated and secreted, (2) serpinA3c/k secretion increases during cellular stress, (3) its appearance in urine reveals a pathophysiological state, and (4) urinary serpinA3 excretion could become a potential biomarker for AKI.

NewBG: A surrogate corticosteroid-binding globulin with an unprecedentedly high ligand release efficacy.

The introduction of ligand-binding sites into proteins and the engineering of molecular allosteric coupling pathways are topical issues in protein design. Here, we show that these issues can be addressed concurrently, using the serpin human α1-antichymotrypsin (ACT) as a model. We have introduced up to 15 amino acid substitutions into ACT, converting it into a surrogate corticosteroid-binding globulin (CBG), thereby creating a new binding globulin (NewBG). Human CBG and ACT share 46% sequence identity, and CBG served as the blue-print for our design, which was guided by side-chain-packing calculations, ITC measurements and crystal structure determinations. Upon transfer of ligand-interacting residues from CBG to ACT and mutation of specific second shell residues, a NewBG variant was obtained, which binds cortisol with 1.5 µM affinity. This novel serpin (NewBG-III) binds cortisol with a 33-fold lower affinity than CBG, but shares a similar ligand-binding profile and binding mode when probed with different steroid ligands and site-directed mutagenesis. An additional substitution, i.e. A349R, created NewBG-III-allo, which introduced an allosteric coupling between ligand binding and the serpin-like S-to-R transition in ACT. In NewBG-III-allo, the proteinase-triggered S-to-R transition leads to a greater than 200-fold reduction in ligand affinity, and crystal structures suggest that this is mediated by the L55V and A349R substitutions. This reduction significantly exceeds the 10-fold reduction in binding affinity observed in human CBG.

Design of an allosterically modulated doxycycline and doxorubicin drug-binding protein.

The allosteric interplay between distant functional sites present in a single protein provides for one of the most important regulatory mechanisms in biological systems. While the design of ligand-binding sites into proteins remains challenging, this holds even truer for the coupling of a newly engineered binding site to an allosteric mechanism that regulates the ligand affinity. Here it is shown how computational design algorithms enabled the introduction of doxycycline- and doxorubicin-binding sites into the serine proteinase inhibitor (serpin) family member α1-antichymotrypsin. Further engineering allowed exploitation of the proteinase-triggered serpin-typical S-to-R transition to modulate the ligand affinities. These design variants follow strategies observed in naturally occurring plasma globulins that allow for the targeted delivery of hormones in the blood. By analogy, we propose that the variants described in the present study could be further developed to allow for the delivery of the antibiotic doxycycline and the anticancer compound doxorubicin to tissues/locations that express specific proteinases, such as bacterial infection sites or tumor cells secreting matrix metalloproteinases.

Effect of simulated air dive and decompression sickness on the plasma proteome of rats.

PURPOSE: Decompression sickness (DCS) is a poorly understood systemic disease caused by inadequate desaturation following a reduction in ambient pressure. Although recent studies highlight the importance of circulating factors, the available data are still puzzling. In this study, we aimed to identify proteins and biological pathways involved in the development of DCS in rats. EXPERIMENTAL DESIGN: Eighteen male Sprague-Dawley rats were subjected to a same simulated air dive to 1000 kPa absolute pressure and divided into two groups: no DCS or DCS. A third control group remained at atmospheric pressure. Venous blood was collected after hyperbaric exposure and the plasma proteomes from four individuals per group were analyzed by using a two-dimensional electrophoresis-based proteomic strategy. RESULTS: Quantitative analysis identified nine protein spots with abundances significantly changed (false discovery rate < 0.1) between the tested conditions. Three protein spots, identified as Apolipoprotein A1, Serine Protease Inhibitor A3K (Serpin A3K), and Alpha-1-antiproteinase, appeared increased in DCS animals but displayed only weak changes. By contrast, one protein spot identified as Transthyretin (TTR) dramatically decreased (i.e. quite disappeared) in animals displaying DCS symptoms. Before diving, TTR level was not different in DCS than nondiving group. CONCLUSION: These results may lead to the use of TTR as an early biomarker of DCS.

Is Alpha-1 Antichymotrypsin Gene Polymorphism a Risk Factor for Primary Intracerebral Hemorrhage? A Case-Control Study and Meta-Analysis.

BACKGROUND: Alpha-1 antichymotrypsin (ACT) signal peptide A/T polymorphism has been suggested to play a role in various brain diseases with arterial wall pathology. We conducted a case-control study and a meta-analysis to evaluate the association between this polymorphism and risk of primary intracerebral hemorrhage. MATERIAL AND METHODS: A total of 188 patients and 200 age- and sex-matched healthy controls were enrolled in our case-control study. The ACT polymorphism was genotyped by PCR-LDR. Further meta-analysis was conducted by searching literature from PUBMED, EMBASE, and Chinese National Knowledge Infrastructure databases until December 2014, then combining data using STATA10.0. RESULTS: Similar genotype distribution was detected between PICH patients and healthy controls (p=0.523). Further analysis based on hypertension and location of hemorrhage did not observe significant association. Multiple logistic regression analysis also failed to identify ACT polymorphism as an independent risk factor for PICH. With regard to meta-analysis, a total of 6 case-control studies including 932 PICH patients and 1140 controls were enrolled. Pooled ORs failed to detect a significant association of ACT signal peptide A/T polymorphism with PICH (dominant model: OR=1.03, 95%CI=0.72-1.46; recessive model: OR=1.08, 95%CI=0.88-1.32). Subgroup analysis based on hypertension revealed no association in hypertensive PICH or in normotensive PICH. CONCLUSIONS: Our case-control study in a Chinese population did not detect a significant association between ACT signal peptide A/T polymorphism and PICH. Moreover, meta-analysis combining data from relevant studies failed to provide evidence for the association. Further well-designed studies with larger sample sizes are warranted to verify our findings.

Tomato cystatin SlCYS8 as a stabilizing fusion partner for human serpin expression in plants.

Studies have reported the usefulness of fusion proteins to bolster recombinant protein yields in plants. Here, we assess the potential of tomato SlCYS8, a Cys protease inhibitor of the cystatin protein superfamily, as a stabilizing fusion partner for human alpha-1-antichymotrypsin (α1ACT) targeted to the plant cell secretory pathway. Using the model expression platform Nicotiana benthamiana, we show that the cystatin imparts a strong stabilizing effect when expressed as a translational fusion with α1ACT, allowing impressive accumulation yields of over 2 mg/g of fresh weight tissue for the human serpin, a 25-fold improvement on the yield of α1ACT expressed alone. Natural and synthetic peptide linkers inserted between SlCYS8 and α1ACT have differential effects on protease inhibitory potency of the two protein partners in vitro. They also have a differential impact on the yield of α1ACT, dependent on the extent to which the hybrid protein may remain intact in the plant cell environment. The stabilizing effect of SlCYS8 does not involve Cys protease inhibition and can be partly reproduced in the cytosol, where peptide linkers are less susceptible to degradation. The effect of SlCYS8 on α1ACT yields could be explained by: (i) an improved translation of the human protein coding sequence; and/or (ii) an overall stabilization of its tertiary structure preventing proteolytic degradation and/or polymerization. These findings suggest the potential of plant cystatins as stabilizing fusion partners for recombinant proteins in plant systems. They also underline the need for an empirical assessment of peptide linker functions in plant cell environments.

Post-transcriptional regulation of α-1-antichymotrypsin by microRNA-137 in chronic heart failure and mechanical support.

BACKGROUND: Better understanding of the molecular mechanisms of remodeling has become a major objective of heart failure (HF) research to stop or reverse its progression. Left ventricular assist devices (LVADs) are being used in patients with HF, leading to partial reverse remodeling. In the present study, proteomics identified significant changes in α-1-antichymotrypsin (ACT) levels during LVAD support. Moreover, the potential role of ACT in reverse remodeling was studied in detail. METHODS AND RESULTS: Expression of ACT mRNA (quantitative-polymerase chain reaction) decreased significantly in post-LVAD myocardial tissue compared with pre-LVAD tissue (n=15; P<0.01). Immunohistochemistry revealed that ACT expression and localization changed during LVAD support. Circulating ACT levels were elevated in HF patients (n=18) as compared with healthy controls (n=6; P=0.001) and normalized by 6 months of LVAD support. Because increasing evidence implicates that microRNAs (miRs) are involved in myocardial disease processes, we also investigated whether ACT is post-transcriptionally regulated by miRs. Bioinformatics analysis pointed miR-137 as a potential regulator of ACT. The miR-137 expression is inversely correlated with ACT mRNA in myocardial tissue. Luciferase activity assays confirmed ACT as a direct target for miR-137, and in situ hybridization indicated that ACT and miR-137 were mainly localized in cardiomyocytes and stromal cells. CONCLUSIONS: High ACT plasma levels in HF normalized during LVAD support, which coincides with decreased ACT mRNA in heart tissue, whereas miR-137 levels increased. MiR-137 directly targeted ACT, thereby indicating that ACT and miR-137 play a role in the pathophysiology of HF and reverse remodeling during mechanical support.

Nuclear α1-antichymotrypsin promotes chromatin condensation and inhibits proliferation of human hepatocellular carcinoma cells.

BACKGROUND & AIMS: α1-Antichymotrypsin (α1-ACT), a member of the serpin family (SERPINA3), is an acute-phase protein secreted by hepatocytes in response to cytokines such as oncostatin M. α1-ACT is a protease inhibitor thought to limit tissue damage produced by excessive inflammation-associated proteolysis. However, α1-ACT also is detected in the nuclei of cells, where its activities are unknown. Expression of α1-ACT is down-regulated in human hepatocellular carcinoma (HCC) tissues and cells; we examined its roles in liver regeneration and HCC proliferation. METHODS: We measured levels of α1-ACT messenger RNA in human HCC samples and healthy liver tissue. We reduced levels of α1-ACT using targeted RNA interference in human HCC (HepG2) and mouse hepatocyte (AML12) cell lines, and overexpressed α1-ACT from lentiviral vectors in Huh7 (HCC) cells and adeno-associated viral vectors in livers of mice. We assessed proliferation, differentiation, and chromatin compaction in cultured cells, and liver regeneration and tumor formation in mice. RESULTS: Reducing levels of α1-ACT promoted proliferation of HCC cells in vitro. Oncostatin M up-regulated α1-ACT expression and nuclear translocation, which inhibited HCC cell proliferation and activated differentiation of mouse hepatocytes. We identified amino acids required for α1-ACT nuclear localization, and found that α1-ACT inhibits cell-cycle progression and anchorage-independent proliferation of HCC cells. HCC cells that overexpressed α1-ACT formed smaller tumors in mice than HCC cells that did not express the protein. α1-ACT was observed to self-associate and polymerize in the nuclei of cells; nuclear α1-ACT strongly bound chromatin to promote a condensed state that could prevent cell proliferation. CONCLUSIONS: α1-ACT localizes to the nuclei of hepatic cells to control chromatin condensation and proliferation. Overexpression of α1-ACT slows the growth of HCC xenograft tumors in nude mice.

Deletion of IκBα activates RelA to reduce acute pancreatitis in mice through up-regulation of Spi2A.

BACKGROUND & AIMS: The transcription factor nuclear factor-κB (NF-κB) (a heterodimer of NF-κB1p50 and RelA) is activated rapidly in acute pancreatitis (AP). However, it is not clear whether NF-κB promotes or protects against AP. We used the NF-κB inhibitor protein, inhibitor of κB (IκB)α, to study the roles of NF-κB in the development of AP in mice. METHODS: IκBα or the combination of IκBα and RelA selectively were deleted from pancreas of mice using the Cre/locus of cross-over P strategy; cerulein or L-arginine were used to induce AP. We performed microarray analyses of the IκBα- and RelA-deficient pancreata. DNA from healthy individuals and patients with acute or chronic pancreatitis were analyzed for variants in coding regions of alpha-1-antichymotrypsin. RESULTS: Mice with pancreas-specific deletion of IκBα had constitutive activation of RelA and a gene expression profile consistent with NF-κB activation; development of AP in these mice was attenuated and trypsin activation was impaired. However, AP was fully induced in mice with pancreas-specific deletion of IκBα and RelA. By using genome-wide expression analysis, we identified a cluster of NF-κB-regulated genes that might protect against the development of AP. The serine protease inhibitor 2A (Spi2a) was highly up-regulated in IκBα-deficient mice. Lentiviral-mediated expression of Spi2A reduced the development of AP in C57BL/6 and RelA-deficient mice. However, we did not correlate any variants of alpha-1-antichymotrypsin, the human homologue of Spi2a, with acute or chronic pancreatitis. CONCLUSIONS: Pancreas-specific deletion of IκBα results in nuclear translocation of RelA and reduces AP induction and trypsin activation in mice after administration of cerulein or L-arginine. Constitutive activation of RelA up-regulates Spi2A, which protects mice against the development of AP.

Genetic factors regulating inflammation and DNA methylation associated with prostate cancer.

BACKGROUND: Prostate cancer (PCa) displays a strong familiarity component and genetic factors; genes regulating inflammation may have a pivotal role in the disease. Epigenetic changes control chromosomal integrity, gene functions and ultimately carcinogenesis. The enzyme glycine-N-methyltransferase (GNMT) contributes to S-adenosylmethionine level regulation and, by affecting DNA methylation, influences gene expression. The genotype and allele distribution of single-nucleotide polymorphisms (SNPs) in the promoter regions of vascular endothelial growth factor (VEGF), interleukin (IL)-10, IL-1ß, alpha-1-antichymotrypsin (ACT) and GNMT genes, the level of global DNA methylation and the influence of GNMT SNP upon DNA methylation in a PCa case-control study have been investigated. METHODS: SNPs of VEGF (rs699947), ACT (rs1884082), IL-1ß (rs16944), IL-10 (rs1800896) and GNMT (rs9462856) genes were assessed by PCR or by real-time PCR methods. DNA methylation was assessed by an ELISA assay. RESULTS: Frequencies of the VEGF AA genotype, the IL-10 A allele and GNMT T allele were higher in PCa. The concomitant presence of the AA genotype of VEGF, the A allele of IL-10 and T allele of GNMT increased the risk of PCa. Total DNA methylation was decreased in PCa; control GNMT T carriers (T+) showed the highest level of DNA methylation. CONCLUSIONS: SNPs in VEGF, IL-10 and GNMT genes might have a synergistic role in the development of PCa. The GNMT T allele may influence PCa risk by affecting DNA methylation and prostate gene expression. Our observations might help implement the screening of unaffected subjects with an increased susceptibility to develop PCa.

The association of ACT -17 A/T polymorphism with Alzheimer's disease: a meta-analysis.

Association studies between Alpha-1-antichymotrypsin (ACT)-17(A > T) polymorphisms and Alzheimer's disease (AD) susceptibility have shown conflicting results. In this investigation, we performed a meta-analysis to assess the purported associations. Subgroup analyses based on ethnicity (Caucasians, East-Asian and American mixed) were also performed including a total of 5,676 AD patients and 5,460 controls for ACT-17. Overall, allele contrast (A vs. T) of ACT -17 polymorphism produced significant results in the worldwide population [P(heterogeneity)=0.01, random-effects (RE) odds ratio (OR) 1.12; 95% CI 1.04-1.21, P=0.003] and in the Caucasian population [P(heterogeneity)=0.03, RE OR1.11 95% CI 1.01-1.24, P=0.04]. Meta-analyses of other genetic contrasts suggested that the A allele carriers are associated with increased susceptibility to AD in variant populations. No significant association was observed in the East-Asian subgroup analysis. In conclusion, ACT-17 variation presents a risk factor for AD in the worldwide population, especially in the Caucasian population.

Recurrent intracerebral hemorrhage in patients with hypertension is associated with APOE gene polymorphism: a preliminary study.

BACKGROUND: Recurrent intracerebral hemorrhage (ICH) in patients with hypertension has been reported in Asia and is attributed to poor control of blood pressure, but there may be a genetic basis. This study evaluates the roles of apolipoprotein E (APOE) and α-1 antichymotrypsin (ACT) genes in patients with recurrent hypertensive ICH and compares patients with nonrecurring hypertensive ICH and normal controls. METHODS: Thirty-three recurrent and 101 nonrecurrent patients with hypertension and ICH were included. The demographic, stroke risk factors, and computed tomographic or magnetic resonance imaging findings were recorded. Magnetic resonance angiography or digital subtraction angiography and vasculitic profile were done in recurrent group to exclude secondary causes of ICH. APOE and ACT gene polymorphisms were assessed with polymerase chain reaction studies in patients with ICH and 188 healthy controls. RESULTS: The demographic and clinical variables were similar in patients with recurrent and nonrecurrent ICH, but patients with recurrent ICH were older (61.1 vs 57.2 years). In the recurrent ICH group, only 7 (10%) out of 69 episodes were lobar; the remaining were deep-seated hematomas. In the nonrecurrent group, 7 (6.9%) patients had lobar ICH. The E2 (odds ratio 4.32; 95% confidence interval 1.65-11.28; P = .003) and E4 alleles of APOE (odds ratio 11.33; 95% confidence interval 5.37-23.02; P < .0001) were significantly related to recurrent ICH compared to healthy controls. The E4 allele was also independently related to recurrent compared to nonrecurrent ICH, even after adjustment for stroke risk factors (odds ratio 25.99; 95% confidence interval 11.65-57.97; P < .0001). ACT gene polymorphism, however, was not related to recurrent ICH compared to controls and nonrecurrent ICH. CONCLUSIONS: APOE polymorphism may contribute to the recurrence of hypertensive ICH.

Serine protease inhibitor A3 in atherosclerosis and aneurysm disease.

Remodeling of extracellular matrix (ECM) plays an important role in both atherosclerosis and aneurysm disease. Serine protease inhibitor A3 (serpinA3) is an inhibitor of several proteases such as elastase, cathepsin G and chymase derived from mast cells and neutrophils. In this study, we investigated the putative role of serpinA3 in atherosclerosis and aneurysm formation. SerpinA3 was expressed in endothelial cells and medial smooth muscle cells in human atherosclerotic lesions and a 14-fold increased expression of serpinA3n mRNA was found in lesions from Apoe-/- mice compared to lesion-free vessels. In contrast, decreased mRNA expression (-80%) of serpinA3 was found in biopsies of human abdominal aortic aneurysm (AAA) compared to non-dilated aortas. Overexpression of serpinA3n in transgenic mice did not influence the development of atherosclerosis or CaCl2-induced aneurysm formation. In situ zymography analysis showed that the transgenic mice had lower cathepsin G and elastase activity, and more elastin in the aortas compared to wild-type mice, which could indicate a more stable aortic phenotype. Differential vascular expression of serpinA3 is clearly associated with human atherosclerosis and AAA but serpinA3 had no major effect on experimentally induced atherosclerosis or AAA development in mouse. However, serpinA3 may be involved in a phenotypic stabilization of the aorta.

Association between α1-antichymotrypsin signal peptide -15A/T polymorphism and the risk of Alzheimer's disease: a meta-analysis.

No consensus has been recently reached at the relationship between the α1-antichymotrypsin (ACT) signal peptide -15A/T polymorphism and Alzheimer's disease (AD) risk. Thus, our study aimed to better assess this association by performing a meta-analysis, including 4,212 cases and 4,039 controls from 29 studies. Odds ratios (ORs) with the 95% confidence interval (CI) were used to assess the strength of relationship between ACT -15A/T polymorphism and AD risk. Overall, a borderline statistically significant association was detected under recessive model comparison in all subjects (AA vs. AT+TT: OR 1.12, 95% CI 1.01-1.25, P = 0.04). But in subgroup analysis by ethnicity, no significant association was found in Caucasians, Asians, or Africans. Moreover, after exclusion of one study which affect the heterogeneity, the ACT A allele and AA genotype were statistically associated with late-onset AD (LOAD) risk (AA vs. TT: OR 1.25, 95% CI 1.06-1.48, P = 0.007, A vs. T: OR 1.12, 95% CI 1.03-1.21, P = 0.008), especially in Caucasians. In conclusion, our study suggests that the common α1-antichymotrypsin signal peptide -15A/T polymorphism may not be a major risk factor for AD. However, the polymorphism is capable of increasing LOAD risk.

Alzheimer's disease, autoimmunity and inflammation. The good, the bad and the ugly.

Alzheimer's disease (AD) has been recognized as the most common cause of sporadic dementia. It represents both a medical and social problem, as it affects 10% of over-65 population. Even if the elderly are the most involved population, aging alone cannot be considered as the only cause of this disease. In this review we wanted to focus on the last hypotheses on the possible causes of this neuronal affection. We focused in particular on the role of inflammation and alteration of the inflammatory status that is typical of the elderly and may lead to chronic inflammation. The inflammation seems to be a cause of neuronal impairment and loss. Some studies have proposed a protective role of antiinflammatory drugs. Then we analyzed the role of genetic polymorphisms of some pro-inflammatory substances that seem to be linked to some cases of dementia. The complement system seems to have a role too, as some factors have been found in senile plaques, representing a possible involvement of classical complement pathway. One of the latest hypotheses is about the role of blood-brain barrier (BBB), as its loss of integrity may lead to a passage of proteins in cerebro spinal fluid (CSF), causing a compromised role of BBB in preserving the brain as an "immune sanctuary".

α1-Antichymotrypsin inactivates staphylococcal cysteine protease in cross-class inhibition.

Staphylococcal cysteine proteases are implicated as virulence factors in human and avian infections. Human strains of Staphylococcus aureus secrete two cysteine proteases (staphopains A and B), whereas avian strains express staphopain C (ScpA2), which is distinct from both human homologues. Here, we describe probable reasons why the horizontal transfer of a plasmid encoding staphopain C between avian and human strains has never been observed. The human plasma serine protease inhibitor α(1)-antichymotrypsin (ACHT) inhibits ScpA2. Together with the lack of ScpA2 inhibition by chicken plasma, these data may explain the exclusively avian occurrence of ScpA2. We also clarify the mechanistic details of this unusual cross-class inhibition. Analysis of mutated ACHT variants revealed that the cleavage of the Leu383-Ser384 peptide bond results in ScpA2 inhibition, whereas hydrolysis of the preceding peptide bond leads to ACHT inactivation. This evidence is consistent with the suicide-substrate-like mechanism of inhibition.

[Microarray analysis of human primary astrocytes activated by beta amyloid peptide and alpha1-antichymotrypsin].

OBJECTIVE: To investigate gene expression of astrocytes under the actions of amyloid peptide Abeta(1-42) and alpha1-antichymotrypsin (ACT) and to explore the characteristics of inflammatory reactions occurring in brain of Alzheimer's patients. METHODS: Human primary astrocytes were cultured to the second passage and then treated with lipopolysaccharide (LPS), Abeta(1-42) (50 micromol/L) and Abeta(1-42)/ACT (50:5 micromol/L) respectively. At 24 h, cells were harvested for total RNA extraction. Gene expression profile was screened by microarray technique. And the function enrichment of differentially expressed genes and the signal transduction pathways involved were analyzed. RESULTS: In comparison with LPS, both Abeta(1-42) and Abeta(1-42)/ACT had demonstrated marked effects on altering the astrocyte gene expression. And the gene up-regulation was predominant. But the gene expression spectrum varied between different groups. Gene ontology analysis showed that Abeta(1-42) up-regulated genes modulated inflammation, oxidative stress and immune response. But Abeta(1-42)/ACT had significant effects on genes related with mitochondrial impairment, apoptosis, oxidative stress, epithelial differentiation and vasculogenesis. The analysis of up-regulated genes, such as interleukin 6 (IL-6) and tumor necrosis factor alpha (TNFalpha), showed that transcriptional factors and downstream genes of signal transduction pathways potentiated further the inflammatory response and cell apoptosis and increased the production of abnormal Abeta. CONCLUSION: Abeta(1-42) induces the inflammation of astrocytes. And the Abeta(1-42)/ACT complex has diverse effects on the gene expression of astrocytes. Thus both proteins play important roles in the activation of astrocytes. In addition, IL-6, TNFalpha and their signal pathways are important in the pathogenic process of Alzheimer's disease.

Is there an association of regulatory region polymorphism in the alpha-1-antichymotrypsin gene with sporadic Alzheimer's disease in the northern Han-Chinese population?

Both invitro and invivo alpha-1-antichymotrypsin (ACT) directly inhibits amyloid beta peptide (Abeta) degradation and promotes Abeta deposition. However, whether the genetic variants in the regulatory region (including the promoter and the two enhancers) of the ACT gene affect susceptibility to Alzheimer's disease (AD) remains controversial. Here, we screened ACT promoter and enhancers in 244 patients with sporadic Alzheimer's disease (SAD) and 205 control patients, both of north Han-Chinese origin. Four single nucleotide polymorphisms (SNP) were found: (i) 11510T/C (rs10145747, named as ACT1); 11496G/A (rs4375593, ACT2); (iii) 11491T/C (rs4508366, ACT3); and (iv) 51G/T (rs1884082, ACT4). Neither individual SNP nor haplotypes were associated with AD onset. We concluded that the effect of the variations in the ACT regulatory region must be very limited, if occurring at all.