Four novel Loci (19q13, 6q24, 12q24, and 5q14) influence the microcirculation in vivo

There is increasing evidence that the microcirculation plays an important role in the pathogenesis of cardiovascular diseases. Changes in retinal vascular caliber reflect early microvascular disease and predict incident cardiovascular events. We performed a genome-wide association study to identify genetic variants associated with retinal vascular caliber. We analyzed data from four population-based discovery cohorts with 15,358 unrelated Caucasian individuals, who are members of the Cohort for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, and replicated findings in four independent Caucasian cohorts (n = 6,652). All participants had retinal photography and retinal arteriolar and venular caliber measured from computer software. In the discovery cohorts, 179 single nucleotide polymorphisms (SNP) spread across five loci were significantly associated (p<5.0×10(-8)) with retinal venular caliber, but none showed association with arteriolar caliber. Collectively, these five loci explain 1.0%-3.2% of the variation in retinal venular caliber. Four out of these five loci were confirmed in independent replication samples. In the combined analyses, the top SNPs at each locus were: rs2287921 (19q13; p = 1.61×10(-25), within the RASIP1 locus), rs225717 (6q24; p?=?1.25×10(-16), adjacent to the VTA1 and NMBR loci), rs10774625 (12q24; p = 2.15×10(-13), in the region of ATXN2,SH2B3 and PTPN11 loci), and rs17421627 (5q14; p?=?7.32×10(-16), adjacent to the MEF2C locus). In two independent samples, locus 12q24 was also associated with coronary heart disease and hypertension. Our population-based genome-wide association study demonstrates four novel loci associated with retinal venular caliber, an endophenotype of the microcirculation associated with clinical cardiovascular disease. These data provide further insights into the contribution and biological mechanisms of microcirculatory changes that underlie cardiovascular disease.     

Discovery of two distinct aminoacyl-tRNA synthetase complexes anchored to the Plasmodium surface tRNA import protein

Aminoacyl-tRNA synthetases (aaRSs) attach amino acids to their cognate transfer RNAs. In eukaryotes, a subset of cytosolic aaRSs is organized into a multisynthetase complex (MSC), along with specialized scaffolding proteins referred to as aaRS-interacting multifunctional proteins (AIMPs). In Plasmodium, the causative agent of malaria, the tRNA import protein (tRip), is a membrane protein that participates in tRNA trafficking; we show that tRip also functions as an AIMP. We identified three aaRSs, the glutamyl-tRNA synthetase (ERS), glutaminyl-tRNA synthetase (QRS), and methionyl-tRNA synthetase (MRS), which were specifically coimmunoprecipitated with tRip in Plasmodium berghei blood stage parasites. All four proteins contain an N-terminal glutathione-S-transferase (GST)–like domain that was demonstrated to be involved in MSC assembly. In contrast to previous studies, further dissection of GST-like interactions identified two exclusive heterotrimeric complexes: the Q-complex (tRip–ERS–QRS) and the M-complex (tRip–ERS–MRS). Gel filtration and light scattering suggest a 2:2:2 stoichiometry for both complexes but with distinct biophysical properties and mutational analysis further revealed that the GST-like domains of QRS and MRS use different strategies to bind ERS. Taken together, our results demonstrate that neither the singular homodimerization of tRip nor its localization in the parasite plasma membrane prevents the formation of MSCs in Plasmodium. Besides, the extracellular localization of the tRNA-binding module of tRip is compensated by the presence of additional tRNA-binding modules fused to MRS and QRS, providing each MSC with two spatially distinct functions: aminoacylation of intraparasitic tRNAs and binding of extracellular tRNAs. This unique host–pathogen interaction is discussed.     

Candidate biomarkers in psychiatric disorders: state of the field

The field of psychiatry is hampered by a lack of robust, reliable and valid biomarkers that can aid in objectively diagnosing patients and providing individualized treatment recommendations. Here we review and critically evaluate the evidence for the most promising biomarkers in the psychiatric neuroscience literature for autism spectrum disorder, schizophrenia, anxiety disorders and post-traumatic stress disorder, major depression and bipolar disorder, and substance use disorders. Candidate biomarkers reviewed include various neuroimaging, genetic, molecular and peripheral assays, for the purposes of determining susceptibility or presence of illness, and predicting treatment response or safety. This review highlights a critical gap in the biomarker validation process. An enormous societal investment over the past 50 years has identified numerous candidate biomarkers. However, to date, the overwhelming majority of these measures have not been proven sufficiently reliable, valid and useful to be adopted clinically. It is time to consider whether strategic investments might break this impasse, focusing on a limited number of promising candidates to advance through a process of definitive testing for a specific indication. Some promising candidates for definitive testing include the N170 signal, an event-related brain potential measured using electroencephalography, for subgroup identification within autism spectrum disorder; striatal resting-state functional magnetic resonance imaging (fMRI) measures, such as the striatal connectivity index (SCI) and the functional striatal abnormalities (FSA) index, for prediction of treatment response in schizophrenia; error-related negativity (ERN), an electrophysiological index, for prediction of first onset of generalized anxiety disorder, and resting-state and structural brain connectomic measures for prediction of treatment response in social anxiety disorder. Alternate forms of classification may be useful for conceptualizing and testing potential biomarkers. Collaborative efforts allowing the inclusion of biosystems beyond genetics and neuroimaging are needed, and online remote acquisition of selected measures in a naturalistic setting using mobile health tools may significantly advance the field. Setting specific benchmarks for well-defined target application, along with development of appropriate funding and partnership mechanisms, would also be crucial. Finally, it should never be forgotten that, for a biomarker to be actionable, it will need to be clinically predictive at the individual level and viable in clinical settings.     

The coexistence of nocturnal sustained hypoxia and obesity additively increases cardiac apoptosis.

Background: nocturnal sustained hypoxia during sleeping time has been reported in severe obesity, but no information regarding the cardiac molecular mechanism in the coexistence of nocturnal sustained hypoxia and obesity is available. This study evaluates whether the coexistence of nocturnal sustained hypoxia and obesity will increase cardiac Fas death receptor and mitochondrial-dependent apoptotic pathway. Methods: 32 lean and 32 obese 5- to 6-mo-old rats with or without nocturnal sustained hypoxia were studied and assigned to one of four subgroups: normoxia lean (NL), normoxia obese (NO), hypoxia lean (HL, 12% O(2) for 8 h and 21% O(2) 16 h/day, 1 wk), and hypoxia obese (HO). The heart weight index, tail cuff plethysmography, echocardiography, hematoxylin-eosin staining, TUNEL assays, Western blotting, and RT-PCR were performed. Results: systolic and diastolic blood pressures in HO were higher than those in NL, and fractional shortening in HO was reduced compared with others. The whole heart weight, the left ventricular weight, the abnormal myocardial architecture, and TUNEL-positive apoptotic cells, as well as the activity of cardiac Fas-dependent and mitochondrial-dependent apoptotic pathway, were significantly increased in obese group or nocturnal sustained hypoxia group and were further increased when obesity and nocturnal sustained hypoxia coexisted, the evidence for which is based on decreases in an anti-apoptotic protein Bcl2 level and Bid and increases in Fas, FADD, pro-apoptotic Bad, BNIP3, cytosolic cytochrome c, activated caspase-8, activated caspase-9, and activated caspase-3. Conclusions: The cardiac Fas receptor- and mitochondrial-dependent apoptotic pathways were more activated in obesity with coexistent nocturnal sustained hypoxia, which may represent one possible apoptotic mechanism for the development of heart failure in obesity with nocturnal sustained hypoxia.     

Vitellogenocytes in the Hepatopancreas of Carcinus maenas and Libinia emarginata (Decapoda brachyura)

Summary

In addition to the ovary, the hepatopanocreas of female decapod crustaceans, Carcinus maenas, and Libinia emarginata is a source of yolk protein. The specific cells in the hepatopancreas that localize vitellogenins on tissue sections are revealed with lipovitellin-specific antiserum. These cells, designated vitellogenocytes, are believed to be responsible for vitellogenin synthesis in the hepatopanocreas. This conclusion is based upon immunolocalization which demonstrates a temporal relationship with vitellogenin synthesis in the hepatopanocreas. Specifically, when the oocytes are most active in vitellogenin uptake, the hepatopanocreas is producing vitellogenins most abundantly. Vitellogenocytes are relatively large and polymorphic, similar to the reserve-inclusion cells that were described by others. Yolk protein was not detected in other cells of the hepatopancreas, male reserve-inclusion cells, or pre-vitellogenic oocytes by the same method of staining. Vitellogenocytes resemble cyanocytes, the source of hemocyanin. Whether the vitellogenocytes and their precursors are related to other populations of hepatocytes, such as cyanocytes, is not known and has not yet been studied.