Neuronal Autophagy: Self-eating or Self-cannibalism in Alzheimer’s Disease

Autophagy is a major intracellular degeneration pathway involved in the elimination and recycling of damaged organelles and long-lived proteins by lysosomes. Many of the pathological factors, which trigger neurodegenerative diseases, can perturb the autophagy activity, which is associated with misfolded protein aggregates accumulation in these disorders. Alzheimer’s disease, the first neurodegenerative disorder between dementias, is characterized by two aggregating proteins, β-amyloid peptide (plaques) and τ-protein (tangles). In Alzheimer’s disease autophagosomes dynamically form along neurites within neuronal cells and in synapses but effective clearance of these structures needs retrograde transportation towards the neuronal soma where there is a major concentration of lysosomes. Maturation of autophago-lysosomes and their retrograde trafficking are perturbed in Alzheimer’s disease, which causes a massive concentration of autophagy elements along degenerating neurites. Transportation system is disturbed along defected microtubules in Alzheimer’s disease brains. τ-protein has been found to control the stability of microtubules, however, phosphorylation of τ-protein or an increase in the total level of τ-protein can cause dysfunction of neuronal cells microtubules. Current evidence has shown that autophagy is developing in Alzheimer’s disease brains because of ineffective degradation of autophagosomes, which hold amyloid precursor protein-rich organelles and secretases important for β-amyloid peptides generation from amyloid precursor. The combination of raised autophagy induction and abnormal clearance of β-amyloid peptide-generating autophagic vacuoles creates circumstances helpful for β-amyloid peptide aggregation and accumulation in Alzheimer’s disease. However, the key role of autophagy in Alzheimer’s disease development is still under consideration today. One point of view suggests that abnormal autophagy induction causes a concentration of autophagic vacuoles rich in amyloid precursor protein, β-amyloid peptide and the elements crucial for its formation, whereas other hypothesis points to marred autophagic clearance or even decrease in autophagic effectiveness playing a role in maturation of Alzheimer’s disease. In this review we present the recent evidence linking autophagy to Alzheimer’s disease and the role of autophagic regulation in the development of full-blown Alzheimer’s disease.     

Cloning and expression analysis of the cytochrome P450c17s enzymes during the reproductive cycle in ovoviviparous Korean rockfish (Sebastes schlegeli)

Cytochrome P450c17 (CYP17, 17α-hydroxylase/17, 20-lyase) plays a critical role in the production of androgens and estrogens in vertebrates. We isolated the full length cDNAs of P450c17-I and P450c17-II from Sebastes schlegeli. The cDNA sequences of P450c17-I and P450c17-II encoded 515 and 533 amino acid residues respectively. The putative P450c17-I and P450c17-II enzymes of Korean rockfish share high sequence identity with that of Japanese flounder (92% and 81%) respectively. Our current study describes that P450c17s of Korean rockfish are mainly expressed in gonads, head kidney and kidney by RT-PCR. Quantitative real-time PCR showed that the expression patterns of Korean rockfish P450c17s were developmental stage-dependency. In addition, the testosterone (T) and gonadosomatic index (GSI) levels further support the important role of P450c17-I during shift in steroidogenesis. Taken together, this study provides information about the Korean rockfish P450c17s characterization and mRNA expression as such helps in further understanding of its function in gonadal development.     

Single nucleotide polymorphism of CD40 in the 5′-untranslated region is associated with ischemic stroke

Objectives

Ischemic stroke is influenced by both environmental and genetic factors. The CD40/CD40L system is related to proinflammatory and prothrombogenic responses, which are involved in the pathophysiology of ischemic stroke. The aim of this study was to evaluate association between the CD40 -1C/T single nucleotide polymorphism (SNP) and ischemic stroke in a Chinese population.

Methods

We conducted a case–control study including 286 ischemic stroke patients and 336 controls. CD40 -1C/T SNP was genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods, and evaluated its relevance to ischemic stroke susceptibility.

Results

Significantly increased ischemic stroke risk was found to be associated with the T allele of CD40 -1C/T (OR = 1.273, 95% CI = 1.016–1.594). The frequencies of CT and TT/CT genotypes of CD40 -1C/T in ischemic stroke patients were significantly higher than those of controls, respectively (for CT: OR = 2.350, 95% CI = 1.601–3.449; for TT/CT: OR = 2.148, 95% CI = 1.479–3.119). And, similar results were obtained after adjusting non-matched variables. We found that the frequency of carried T genotypes (TT and TT/CT) was significantly increased in patients with history of stroke compared with patients without (for TT: OR = 6.538, 95%CI = 1.655–25.833; for TT/CT: OR = 3.469, 95%CI = 1.031–11.670), respectively.

Conclusions

The findings suggested that the CD40 -1C/T polymorphism might contribute to the susceptibility to ischemic stroke in the Chinese population, and might be associated with history of previous stroke.     

The complete mitochondrial genome sequence and gene organization of the mud crab (Scylla paramamosain) with phylogenetic consideration

The complete mitochondrial genome is of great importance for better understanding the genome-level characteristics and phylogenetic relationships among related species. In the present study, we determined the complete mitochondrial genome DNA sequence of the mud crab (Scylla paramamosain) by 454 deep sequencing and Sanger sequencing approaches. The complete genome DNA was 15,824 bp in length and contained a typical set of 13 protein-coding genes, 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes and a putative control region (CR). Of 37 genes, twenty-three were encoded by the heavy strand (H-strand), while the other ones were encoded by light strand (L-strand). The gene order in the mitochondrial genome was largely identical to those obtained in most arthropods, although the relative position of gene tRNA^His differed from other arthropods. Among 13 protein-coding genes, three (ATPase subunit 6 (ATP6), NADH dehydrogenase subunits 1 (ND1) and ND3) started with a rare start codon ATT, whereas, one gene cytochrome c oxidase subunit I (COI) ended with the incomplete stop codon TA. All 22 tRNAs could fold into a typical clover-leaf secondary structure, with the gene sizes ranging from 63 to 73 bp. The phylogenetic analysis based on 12 concatenated protein-coding genes showed that the molecular genetic relationship of 19 species of 11 genera was identical to the traditional taxonomy.     

Comparison and Effects of Acute Lamotrigine Treatment on Extracellular Excitatory Amino Acids in the Hippocampus of PTZ-Kindled Epileptic and PTZ-Induced Status Epilepticus Rats

In this communication, the effect of acute treatment with lamotrigine (LTG) was investigated on release of main excitatory amino acids (EAA) such as glutamate (Glu) and aspartate (Asp) in the hippocampus of pentylenetetrazol (PTZ)-induced and PTZ-kindled freely moving rats using micro dialysis. The results show that, levels of Glu and Asp significantly increased in the rat hippocampus during the seizure/interical periods for PTZ-status epilepticus (SE) and PTZ-kindled epileptic (EP) rats. The levels of Glu and Asp increased more in EP rat hippocampus than in SE rat hippocampus. After administration of 20 mg/kg LTG, the levels of Glu and Asp significantly decreased in the SE and EP rat hippocampus. The results indicate that: (a) excitability of the PTZ-kindled epileptogenic model is higher than that of the status epilepticus model; (b) the modulation of LTG on the EAA neurotransmitters certainly plays an important role in antiepileptic efficacy, especially in PTZ-kindled epileptic model where the release of EAA was influenced more markedly by acute application of 20 mg/kg LTG.     

Association of the macrophage migration inhibitory factor gene − 173G/C polymorphism with inflammatory bowel disease: A meta-analysis of 4296 subjects

A variety of epidemiologic studies have focused on the association between macrophage migration inhibitory factor (MIF) gene − 173G/C polymorphism and inflammatory bowel disease (IBD). However, results in different studies have been inconsistent. In order to derive a more precise estimation of the associations, we performed this meta-analysis and systematic searches of electronic databases PubMed and Web of Science (up to April 30, 2013). Based on our search criteria, a total of seven eligible studies concerning the MIF − 173G/C polymorphism and IBD risk were included in the final meta-analysis, comprising 2162 IBD cases and 2134 controls. Significant association was found between MIF − 173G/C polymorphism and the risk of IBD when all studies were pooled into the meta-analysis (for C allele vs. G allele: OR = 1.25, 95% CI = 1.12–1.41, p = 0.000; for C/C vs. G/G: OR = 1.71, 95% CI = 1.23–2.39, p = 0.002; for C/C + G/C vs. G/G: OR = 1.24, 95% CI = 1.09–1.42, p = 0.002; for C/C vs. G/C + G/G: OR = 1.67, 95% CI = 1.20–2.33, p = 0.002). Heterogeneity and publication bias did not exist in the overall comparisons. The present meta-analysis suggests an association between the MIF − 173G/C polymorphism and IBD risk. However, due to few studies and the selection bias existed in some studies, the results should be interpreted with caution.     

A CRYGC gene mutation associated with autosomal dominant pulverulent cataract

Purpose

To describe at molecular level a family with pulverulent congenital cataract associated with a CRYGC gene mutation.

Methods

One family with several affected members with pulverulent congenital cataract and 230 healthy controls were examined. Genomic DNA from leukocytes was isolated to analyze the CRYGA-D cluster, CX46, CX50 and MIP genes through high-resolution melting curve and DNA sequencing.

Results

DNA sequencing in the affected members revealed the c.143G>A mutation (p.R48H) in exon 2 of the CRYGC gene; 230 healthy controls and ten healthy relatives were also analyzed and none of them showed the c.143G>A mutation. No other polymorphisms or mutations were found to be present.

Conclusion

In the present study, we described a family with pulverulent congenital cataract that segregated the c.143G>A mutation (p.R48H) in the CRYGC gene. A few mutations have been described in the CRYGC gene in autosomal dominant cataract, none of them with pulverulent cataract making clear the clinical heterogeneity of congenital cataract. This mutation has been associated with the phenotype of congenital cataract but also is considered an SNP in the NCBI data base. Our data and previous report suggest that p.R48H could be a disease-causing mutation and not an SNP.     

Association between interleukin-10 promoter polymorphisms and endometriosis: A meta-analysis

To investigate the influence of the interleukin-10 gene promoter polymorphisms on the susceptibility of endometriosis, we examined the association by performing a meta-analysis. The PubMed, Embase, HuGE Navigator and CNKI were searched to identify eligible studies. We then conducted a meta-analysis to examine the association between interleukin-10 gene promoter polymorphisms and endometriosis. Eight case–control studies which examined the association between the IL-10 gene promoter polymorphisms and the susceptibility to endometriosis were finally included in the meta-analysis. Meta-analysis of the IL-10 − 592 A/C polymorphisms showed a significant increased risk of endometriosis in the overall and Asian population in all genetic models and allele contrast. However, meta-analysis of the IL-10 − 1082 A/G and IL-10 − 819 T/C polymorphisms showed no association with endometriosis in all genetic models and allele contrast in the overall and Asian population samples. In addition, there was not a significant association between the IL-10 − 592 A/C gene promoter polymorphisms with the severity of endometriosis.