Showing posts with label complement receptor 1. Show all posts
Showing posts with label complement receptor 1. Show all posts

Gut microbiota in early pediatric multiple sclerosis: a case-control study. - PubMed - NCBI

BACKGROUND AND PURPOSE:
Alterations in the gut microbial community composition may be influential in neurological disease. Microbial community profiles were compared between early onset pediatric multiple sclerosis (MS) and control children similar for age and sex.

METHODS:
Children ≤18 years old within 2 years of MS onset or controls without autoimmune disorders attending a University of California, San Francisco, USA, pediatric clinic were examined for fecal bacterial community composition and predicted function by 16S ribosomal RNA sequencing and phylogenetic reconstruction of unobserved states (PICRUSt) analysis. Associations between subject characteristics and the microbiota, including beta diversity and taxa abundance, were identified using non-parametric tests, permutational multivariate analysis of variance and negative binomial regression.

RESULTS:
Eighteen relapsing-remitting MS cases and 17 controls (mean age 13 years; range 4-18) were studied. Cases had a short disease duration (mean 11 months; range 2-24) and half were immunomodulatory drug (IMD) naïve. Whilst overall gut bacterial beta diversity was not significantly related to MS status, IMD exposure was (Canberra, P < 0.02). However, relative to controls, MS cases had a significant enrichment in relative abundance for members of the Desulfovibrionaceae (Bilophila, Desulfovibrio and Christensenellaceae) and depletion in Lachnospiraceae and Ruminococcaceae (all P and q < 0.000005). Microbial genes predicted as enriched in MS versus controls included those involved in glutathione metabolism (Mann-Whitney, P = 0.017), findings that were consistent regardless of IMD exposure.

CONCLUSIONS:
In recent onset pediatric MS, perturbations in the gut microbiome composition were observed, in parallel with predicted enrichment of metabolic pathways associated with neurodegeneration. Findings were suggestive of a pro-inflammatory milieu."




Human complement receptor type 1/CD35 is an Epstein-Barr Virus receptor.

Epstein-Barr virus (EBV) attachment to primary B cells initiates virus entry. Although CD21 is the only known receptor for EBVgp350/220, a recent report documents EBV-infected B cells from a patient genetically deficient in CD21. On normal resting B cells, CD21 forms two membrane complexes: one with CD19 and another with CD35 (CR1) . Whereas the CD21/CD19 complex is widely retained on immortalized and B cell tumor lines, the related complement-regulatory protein CD35 is lost. To determine the role(s) of CD35 in initial infection, we transduced a CD21-negative pre-B cell and myeloid leukemia line with CD35, CD21, or both. Cells expressing CD35 alone bound gp350/220 and became latently infected when the fusion receptor HLA II was coexpressed. Temporal, biophysical, and structural characteristics of CD35-mediated infection were distinct from CD21. Identification of CD35 as an EBV receptor uncovers a salient role in primary infection, addresses unsettled questions of virus tropism, and underscores the importance of EBVgp350/220 for vaccine development.
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Complement Receptor 1 Variants Confer Protection from Severe Malaria in Odisha, India.


In Plasmodium falciparum infection, complement receptor-1 (CR1) on erythrocyte's surface and ABO blood group play important roles in formation of rosettes which are presumed to be contributory in the pathogenesis of severe malaria. Although several studies have attempted to determine the association of CR1 polymorphisms with severe malaria, observations remain inconsistent. Therefore, a case control study and meta-analysis was performed to address this issue.

METHODS:

Common CR1 polymorphisms (intron 27 and exon 22) and blood group were typed in 353 cases of severe malaria (SM) [97 cerebral malaria (CM), 129 multi-organ dysfunction (MOD), 127 non-cerebral severe malaria (NCSM)], 141 un-complicated malaria and 100 healthy controls from an endemic region of Odisha, India. Relevant publications for meta-analysis were searched from the database.

RESULTS:

The homozygous polymorphisms of CR1 intron 27 and exon 22 (TT and GG) and alleles (T and G) that are associated with low expression of CR1 on red blood cells, conferred significant protection against CM, MOD and malaria deaths. Combined analysis showed significant association of blood group B/intron 27-AA/exon 22-AA with susceptibility to SM (CM and MOD). Meta-analysis revealed that the CR1 exon 22 low expression polymorphism is significantly associated with protection against severe malaria.

CONCLUSIONS:

The results of the present study demonstrate that common CR1 variants significantly protect against severe malaria in an endemic area.

Study reveals multiple mechanisms may play role in Alzheimer's

(Medical Xpress)—Researchers investigating a known gene risk factor for Alzheimer's disease 9 complement receptor  1 ) discovered it is associated with lower levels of beta amyloid—a brain protein involved in Alzheimer's—in cognitively healthy older people. The findings suggest that a mechanism other than one related to beta amyloid accumulation may influence disease risk associated with the gene. The study, by researchers at the National Institute on Aging (NIA) at the National Institutes of Health, was published online September 27, 2012 in the journal Biological Psychiatry.

Read more at: http://medicalxpress.com/news/2012-10-reveals-multiple-mechanisms-role-alzheimer.html#jCp

PICALM and CR1 Variants are not Associated with Sporadic Alzheimer's Disease in Chinese Patients.

PICALM and CR1 Variants are not Associated with Sporadic Alzheimer's Disease in Chinese Patients.

As with pre GWAS studies, the problems of replication will not go away. It is quite possible that there are many ways of causing Alzheimer's disease, particularly because of the organisation of gene subsets into signalling networks, and because of relationships betwen genes and risk factors.

Risk factors: Alzheimer's : Kegg pathways Alzheimer's
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The atherogenicbacterium Porphyromonas gingivalis evades circulating phagocytes by adhering to erythrocytes.

Porphyromonas gingivalis is one of the causes of gum disease which has been linked to both atherosclerosis and Alzheimer's disease: The bacteria stick to complement component C3 and in doing so interfere with complement receptor 1 on red blood cells. Herpes simplex and influenza viruses also bind to complement receptor 1 Refs
A neat link between susceptibility genes (CR1) and risk factors

Risk factors: Alzheimer's :
Kegg pathways
Alzheimer's  Herpes simplex infection 
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Complement receptor 1 polymorphisms and risk of late-onset Alzheimer's disease.

Complement receptor 1 is a risk factor for Alzheimer's disease in China, while PICALM was not See Posts

Clusterin was also unrelated in a Russian study (see posts). Good news for complement pathways, which are involved in pathogen defense and in beta-amyloid clearance. RSS feed
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Association of CR1, CLU and PICALM with Alzheimer's disease in a cohort of clinically characterized and neuropathologically verified individuals.

This study confirmed APOE , clusterin , complement receptor 1 and PICALM, and also angiotensin converting enzyme ACE and cystatin CST3 as Alzheimer's disease risk factors

However, note that PICALM did not turn up positive in a chinese study Yu et al, 20101  supporting the notion that genetic associations may cluster in geographical hot and cold spots.  See database
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Implication of the immune system in Alzheimer's disease: evidence from genome-wide pathway analysis.


Previous data from old-fashioned case-controls had already implicated a number of immune-related genes. Clusterin and complement receptor 1 also fall into this category See database