Reduced Annexin A1 Expression Associates with Disease Severity and Inflammation in Multiple Sclerosis Patients

Chronic neuroinflammation is a key pathological hallmark of multiple sclerosis (MS) that suggests that resolution of inflammation by specialized proresolving molecules is dysregulated in the disease. Annexin A1 (ANXA1) is a protein induced by glucocorticoids that facilitates resolution of inflammation through several mechanisms that include an inhibition of leukocyte recruitment and activation. In this study, we investigated the ability of ANXA1 to influence T cell effector function in relapsing/remitting MS (RRMS), an autoimmune disease sustained by proinflammatory Th1/Th17 cells. Circulating expression levels of ANXA1 in naive-to-treatment RRMS subjects inversely correlated with disease score and progression. At the cellular level, there was an impaired ANXA1 production by CD4⁺CD25^- conventional T and CD4⁺RORγt⁺ T (Th17) cells from RRMS subjects that associated with an increased migratory capacity in an in vitro model of blood brain barrier. Mechanistically, ANXA1 impaired monocyte maturation secondarily to STAT3 hyperactivation and potently reduced T cell activation, proliferation, and glycolysis. Together, these findings identify impaired disease resolution pathways in RRMS caused by dysregulated ANXA1 expression that could represent new potential therapeutic targets in RRMS.

The restorative role of annexin A1 at the blood-brain barrier

Annexin A1 is a potent anti-inflammatory molecule that has been extensively studied in the peripheral immune system, but has not as yet been exploited as a therapeutic target/agent. In the last decade, we have undertaken the study of this molecule in the central nervous system (CNS), focusing particularly on the primary interface between the peripheral body and CNS: the blood-brain barrier. In this review, we provide an overview of the role of this molecule in the brain, with a particular emphasis on its functions in the endothelium of the blood-brain barrier, and the protective actions the molecule may exert in neuroinflammatory, neurovascular and metabolic disease. We focus on the possible new therapeutic avenues opened up by an increased understanding of the role of annexin A1 in the CNS vasculature, and its potential for repairing blood-brain barrier damage in disease and aging.

The Possible Involvement of HLA Class III Haplotype (RAGE, HSP70 and TNF Genes) in Alzheimer's Disease

In the central nervous system Hsp70s seems to have a protective role in repair and removal of cellular proteins damaged by stress conditions. A protective role of Hsp70 was also shown in Alzheimer Disease. The HSP70-1 +190 G/C polymorphism is located in the gene 5'UTR region and it is implicated in alteration of the transcription binding factor; HSP70-2 +1267 A/G causes a silent mutation in the coding region and it seems to influence the mechanism of mRNA translation; HSP70-hom +2437 A/G causes a substitution Met → The (M493T) in the coding region and it seems to influence the bond with the substrate and therefore on the chaperone activity of hsp70. The aim of our study will be to investigate Alzheimer susceptibility to Hsp70 polymorphisms, taking into account our previous findings on HLA class III region, and to hypothesize a role of HLA class III haplotype configuration based on the variants of three genes: RAGE, HSP70 and TNF. We studied these polymorphisms with PCR-RFLP and PCR-TSP. We investigated 173 AD patients and 211 control subjects. Our results have shown a statistically significant decrease of the C allele frequency of the HSP70-1 +190 G/C polymorphism in AD patients vs controls (P value = 0,018), as well as the G allele of HSP70-2 +1267 G/A (p value = 0,02). We focalized our attention on haplotype reconstruction. We have observed a significant statistically decrease of GGT haplotype frequency (empirical p-value=0.0133 ); GAT haplotype was statistically significant increase in AD patients compared with control (empirical p-value=0.007). The total HLA class III haplotype are reconstructed. The causative haplotypes are the following ones: TTGATGGG ( p value =0,005; empirical p =0,0042); TTGATAGG (p value =0,45; empirical p =0,034). Patients with these haplotypes may show an earlier onset of the disease than patients with TTGGTGGG (p value=0,0138; empirical p =0,0102); TTCGTGGG (p value=0,021; empirical p =0,017); TTCGTGGA (p value =0,058; empirical p =0,043) haplotypes. The overall variation of the haplotypes formed by the RAGE and TNF and HSP70 variants influenced the presence of the AD phenotype (omnibus association LR test p-value 0.00185), HSP701 and HSP702 showed independent effect on AD risk after adjusting for the effect of the entire haplotype (conditional LR test p-value=0.0114 and p-value=0.0044 respectively). These data confirm the involvement of HLA class III in AD.

Estrogen protects the blood-brain barrier from inflammation-induced disruption and increased lymphocyte trafficking

Sex differences have been widely reported in neuroinflammatory disorders, focusing on the contributory role of estrogen. The microvascular endothelium of the brain is a critical component of the blood-brain barrier (BBB) and it is recognized as a major interface for communication between the periphery and the brain. As such, the cerebral capillary endothelium represents an important target for the peripheral estrogen neuroprotective functions, leading us to hypothesize that estrogen can limit BBB breakdown following the onset of peripheral inflammation. Comparison of male and female murine responses to peripheral LPS challenge revealed a short-term inflammation-induced deficit in BBB integrity in males that was not apparent in young females, but was notable in older, reproductively senescent females. Importantly, ovariectomy and hence estrogen loss recapitulated an aged phenotype in young females, which was reversible upon estradiol replacement. Using a well-established model of human cerebrovascular endothelial cells we investigated the effects of estradiol upon key barrier features, namely paracellular permeability, transendothelial electrical resistance, tight junction integrity and lymphocyte transmigration under basal and inflammatory conditions, modeled by treatment with TNFα and IFNγ. In all cases estradiol prevented inflammation-induced defects in barrier function, action mediated in large part through up-regulation of the central coordinator of tight junction integrity, annexin A1. The key role of this protein was then further confirmed in studies of human or murine annexin A1 genetic ablation models. Together, our data provide novel mechanisms for the protective effects of estrogen, and enhance our understanding of the beneficial role it plays in neurovascular/neuroimmune disease.

The human leukocyte antigen class III haplotype approach: new insight in Alzheimer's disease inflammation hypothesis

The Alzheimer's disease "inflammation hypothesis" has emerged only recently, suggesting the risk of developing AD might be influenced by variants of genes encoding for inflammatory mediators. In order to investigate in this direction, genomic DNA from 194 Italian AD cases and 454 healthy controls matched by gender and ethnicity was analyzed for the Receptor for Advanced Glycation End products (RAGE, HLA class III-centromere portion) -374 and - 429 SNPs and for the Tumor Necrosis Factor-alpha (TNF-α, HLA class III-telomere portion) -857, -308 and -238 SNPs by RFLP and Real Time PCR. Our data show statistically significant deviations between AD patients and healthy controls concerning RAGE -374 SNP genotype (TT: p=0.0084) and allele (T, A: p=0.0081) frequencies; TNF-α -308 SNP AA genotype (p=0.0433) and TNF-α -238 SNP genotype (GG: p=0.0138) and allele (G, A: p=0.0151) frequencies. Furthermore, significant differences between the study groups and regarding RAGE TC (p=0.05) and AC (p=0.009) haplotypes are present, while TNF-α haplotype reconstruction point out a statistically significant difference between patients and controls regarding AGG haplotype (p=0.002). Finally, from the combination of the individually significant SNPs of the two genes (RAGE -374, TNF-α -238 and -308) we performed an HLA class III haplotype reconstruction finding significant differences between AD subjects and controls regarding the TAG (p=0.019) and TGA (p=0.008) haplotypes. The implication of these haplotypes with the disease points to a possible involvement of entire HLA class III region in AD susceptibility.

Brain-derived neurotrophic factor gene variants and Alzheimer disease: an association study in an Alzheimer disease Italian population

Brain-derived neurotrophic factor (BDNF) promotes neuronal survival during development and protects neurons from insults of various kinds. Changes in production of BDNF have been reported in differing neurodegenerative pathologies and, in particular, in Alzheimer disease (AD). We studied 200 AD patients and 408 healthy controls for BDNF Val66Met(G196A) polymorphism, 200AD and 384 healthy controls for BDNF 270 C/T polymorphism, and 200AD and 393 healthy controls for BDNF 11757 G/C polymorphism by restriction fragment length polymorphism (RFLP) and real-time PCR. Our results indicated that the 11757 G/C BDNF polymorphism was significantly associated with AD. A statistically significant increase of GG genotype frequency in AD versus healthy subjects (p=0.0331) was observed, whereas the CG genotype demonstrates a statistically significant decrease of frequency in AD patients versus controls (p=0.0194). We focused our attention on haplotype reconstruction: A statistically significant decrease of the TAC haplotype frequency in AD patients versus healthy controls group (p=0.005) and a statistically significant increase of the CAC haplotype frequency in patients versus control (p=0.019) was demonstrated. We then studied the haplotype frequencies dividing patients according to gender. A statistically significant increase of the CAC haplotype in the male AD group compared with male healthy controls (p=0.041) was found, whereas a statistically significant decrease of TAC haplotype frequency in AD females versus healthy females (p=0.005) and a statistically significant increase of CAC haplotype frequency in female patients versus healthy females (p=0.019) was noticed. We propose that these haplotypes could be a further effective marker for AD.

HLA class III genes involvement in Kawasaki disease: a case-control study in Caucasian population

Kawasaki disease (KD) is an acute, multisystemic, febrile vasculitis of unknown aetiology, which affects young children mainly under 5 years of age. The clinical variability has until now prevented to decrypt KD aetiological factors. Recently, the importance of genetics and the pivotal role of the immune system have emerged. To investigate in this direction, genomic DNA from 74 Caucasian KD cases and 440 healthy controls has been analysed to characterize functional polymorphisms of relevant HLA class III genes: AGER -429 and -374, TNF -857, -308 and -238, HSPA1A +190, HSPA1B +1267 and HSPA1L +2437. Allele, genotype and haplotype frequencies were therefore compared with the chi-squared test and Fisher's exact test. Our data showed significant deviations between patients with Kawasaki disease and controls concerning the TNF -308 polymorphism genotype (GG: P = 0.0449) and allele (G,A: P = 0.0433) and -238 polymorphism genotype frequencies (AA: P = 0.0351). Moreover, we found differences concerning the HSPA1A +190 polymorphism (GC: P = 0.0317) and the HSPA1L +2437 polymorphism (TT: P = 0.0072; TC: P = 0.0250; T: P = 0.0037; C: P = 0.0037). The calculation of TNF -238 and HSPA1L haplotype frequencies also pointed out a statistically significant decrease in patients of CG haplotype (P = 0.0001), which could have a role in protecting from the inflammatory processes that characterize the disease progression. The results obtained point to a possible involvement of the entire HLA class III region in KD susceptibility.