Low Density Lipoproteins Promote Unstable Calcium Handling Accompanied by Reduced SERCA2 and Connexin-40 Expression in Cardiomyocytes

The damaging effects of high plasma levels of cholesterol in the cardiovascular system are widely known, but little attention has been paid to direct effects on cardiomyocyte function. We therefore aimed at testing the hypothesis that Low Density Lipoprotein (LDL) cholesterol affects calcium dynamics and signal propagation in cultured atrial myocytes. For this purpose, mRNA and protein expression levels were determined by real time PCR and western blot analysis, respectively, and intracellular calcium was visualized in fluo-4 loaded atrial HL-1 myocyte cultures subjected to field stimulation. At low stimulation frequencies all cultures had uniform calcium transients at all tested LDL concentrations. However, 500 µg LDL/mL maximally reduced the calcium transient amplitude by 43% from 0.30±0.04 to 0.17±0.02 (p<0.05). Moreover, LDL-cholesterol dose-dependently increased the fraction of alternating and irregular beat-to-beat responses observed when the stimulation interval was shortened. This effect was linked to a concurrent reduction in SERCA2, RyR2, IP3RI and IP3RII mRNA levels. SERCA2 protein levels were also reduced by 43% at 200 µg LDL/mL (p<0.05) and SR calcium loading was reduced by 38±6% (p<0.001). By contrast, HDL-cholesterol had no significant effect on SERCA expression or SR calcium loading. LDL-cholesterol also slowed the conduction velocity of the calcium signal from 3.2+0.2 mm/s without LDL to 1.7±0.1 mm/s with 500 µg LDL/mL (p<0.05). This coincided with a reduction in Cx40 expression (by 44±3%; p<0.05 for mRNA and by 79±2%; p<0.05 for Cx40 protein at 200 µg/ml LDL) whereas the Cx-43 expression did not significantly change. In conclusion, LDL-cholesterol destabilizes calcium handling in cultured atrial myocytes subjected to rapid pacing by reducing SERCA2 and Cx40 expression and by slowing the conduction velocity of the calcium signal.     

Seasonal cycles of plasma testosterone and cortisol in the wild rabbit (Oryctolagus cuniculus algirus Loche) of Zembra Island, studied in its natural biotope and in captivity

Annual variations in plasma testosterone and cortisol levels were determined in male wild rabbits caught monthly in their natural biotope (Zembra island). For comparison, a group of warrens was hold in semi-captivity close to Tunis. In both conditions plasma testosterone concentrations were low from January to September and peak values were observed in October. Captive warrens exhibited a clear cut annual rhythm in plasma cortisol levels also and ether stress resulted in a very large increase of cortisolemia. In rabbits caught in ther habitat however, cortisol concentrations were always extremely high throughout the year, probably due to stressing conditions. Interestingly, wild rabbits of Zembra island appear to subsist from a very remote past without any contact with other strains. As to Zembra, it is a hardly get-at-able, uninhabited island which is a part of a strictly protected natural reserve and constitutes a fairly useful and valuable ecosystem.     

The molecular machinery of germ line specification

Germ cells occupy a unique position in animal reproduction, development, and evolution. In sexually reproducing animals, only they can produce gametes and contribute genetically to subsequent generations. Nonetheless, germ line specification during embryogenesis is conceptually the same as the specification of any somatic cell type: germ cells must activate a specific gene regulatory network in order to differentiate and go through gametogenesis. While many genes with critical roles in the germ line have been characterized with respect to expression pattern and genetic interactions, it is the molecular interactions of the relevant gene products that are ultimately responsible for germ cell differentiation. This review summarizes the current state of knowledge on the molecular functions and biochemical connections between germ line gene products. We find that homologous genes often interact physically with the same conserved molecular partners across the metazoans. We also point out cases of nonhomologous genes from different species whose gene products play analogous biological roles in the germ line. We suggest a preliminary molecular definition of an ancestral “pluripotency module” that could have been modified during metazoan evolution to become specific to the germ line. Mol. Reprod. Dev. 77: 3–18, 2010. © 2009 Wiley‐Liss, Inc.     

Split Nano luciferase complementation for probing protein‐protein interactions in plant cells

Deciphering protein‐protein interactions (PPIs) is fundamental for understanding signal transduction pathways in plants. The split firefly luciferase (Fluc) complementation (SLC) assay has been widely used for analyzing PPIs. However, concern has risen about the bulky halves of Fluc interfering with the functions of their fusion partners. Nano luciferase (Nluc) is the smallest substitute for Fluc with improved stability and luminescence. Here, we developed a dual‐use system enabling the detection of PPIs through the Nluc‐based SLC and co‐immunoprecipitation assays. This was realized by coexpression of two proteins under investigation in fusion with the HA‐ or FLAG‐tagged Nluc halves, respectively. We validated the robustness of this system by reproducing multiple previously documented PPIs in protoplasts or Agrobacterium‐transformed plants. We next applied this system to evaluate the homodimerization of Arabidopsis CERK1, a coreceptor of fungal elicitor chitin, and its heterodimerization with other homologs in the absence or presence of chitin. Moreover, split fragments of Nluc were fused to two cytosolic ends of Arabidopsis calcium channels CNGC2 and CNGC4 to help sense the allosteric change induced by the bacterial elicitor flg22. Collectively, these results demonstrate the usefulness of the Nluc‐based SLC assay for probing constitutive or inducible PPIs and protein allostery in plant cells.     

Psychological and clinical characteristics of female patients with spontaneous coronary artery dissection

Aims

Spontaneous coronary artery dissection (SCAD) is increasingly recognised as a cause of myocardial infarction, but psychological characteristics of patients with SCAD have not yet been extensively investigated. We assessed the prevalence of a broad range of psychological and clinical factors, and their inter-relationships in patients with a history of SCAD. Furthermore, we investigated whether specific clusters of patients with SCAD can be identified.

Methods

Participants were recruited between March and May 2019 from a Dutch SCAD database and completed online questionnaires. Clinical information was verified by review of medical records. Participants were predominantly female (172/183; 94%). Analyses focused on the 172 female patients (mean age 52.0 ± 7.5 years, 37% postmenopausal).

Results

The most common comorbidities of SCAD were migraine (52%), fibromuscular dysplasia (FMD; 29%), chronic pain (29%), and tinnitus (28%). Six women (3%) had pregnancy-associated SCAD. Traditional cardiovascular risk factors were rare (<10%), except for hypertension (31%). Psychological assessment indicated high levels of perceived stress (PSS-10 ≥14; 50%), fatigue (FAS-10 ≥22; 56%), and a frequent history of burnout (25%). The prevalence of depression (9%) and anxiety (12%) was relatively low. Three clusters were identified: (A) FMD and chronic non-ischaemic conditions (tinnitus, chronic pain, and irritable bowel syndrome); (B) migraine; and (C) none of these conditions.

Conclusion

This study shows that perceived stress and fatigue are common in patients with SCAD, in addition to prevalent comorbid FMD, migraine, tinnitus, and non-ischaemic pain conditions. These factors may add to developing tailored rehabilitation programmes for patients with SCAD.

     

Characterization of Polar and Non‐Polar Compounds of House Edible Bird's Nest (EBN) from Johor,Malaysia

This work investigated the polar (PC: protein, amino acid and metabolite) and non‐polar (NPC: fatty acid) compounds and bioactivity characteristics of the EBN harvested from the state of Johor in Malaysia. The electrophoretic gels exhibited 15 protein bands (16–173 kD) with unique protein profile. Amino acids analysis by AccQ?Tag method revealed 18 types of amino acids in EBN. Metabolite profiling was performed using High‐Performance Liquid Chromatography coupled with Quadrupole Time‐of‐Flight Mass Spectrometer (HPLC‐QTOF/MS) technique and a total of 54 compounds belonging to different groups were detected and identified. These findings help to uncover the relation of therapeutic activity of EBN. The EBN was further extracted with AcOEt and BuOH. The AcOEt extract was fractionated into three fractions (F₁?F₃), and the high triglyceride content in F₂ was verified by gC‐FID. The three groups of fatty acids discovered in EBN are 48.43 % of poly‐unsaturated (PUFA), 25.35 % of saturated fatty acids (SFA) and 24.74 % of mono‐unsaturated fat (MUFA). This is the first time to report results ofEBN, BuOH, and AcOEt extracts and of fraction F₂ (TEBN) on their analysis for their antioxidant activities by DPPH, ABTS and catalase assay and for their paraoxonase and anti‐tyrosinase activities. The results showed that TEBN exhibited the significant bioactivity in all assays. These findings suggest that TEBN is a good source for natural bioactive compounds in promoting body vigor. Current work widened the content of EBN especially on the triglyceride and also marked the content of specific location (Johor, Malaysia) of EBN origin.     

Mouse genetics identifies unique and overlapping functions of fibroblast growth factor receptors in keratinocytes

Fibroblast growth factors (FGFs) are key regulators of tissue development, homeostasis and repair, and abnormal FGF signalling is associated with various human diseases. In human and murine epidermis, FGF receptor 3 (FGFR3) activation causes benign skin tumours, but the consequences of FGFR3 deficiency in this tissue have not been determined. Here, we show that FGFR3 in keratinocytes is dispensable for mouse skin development, homeostasis and wound repair. However, the defect in the epidermal barrier and the resulting inflammatory skin disease that develops in mice lacking FGFR1 and FGFR2 in keratinocytes were further aggravated upon additional loss of FGFR3. This caused fibroblast activation and fibrosis in the FGFR1/FGFR2 double‐knockout mice and even more in mice lacking all three FGFRs, revealing functional redundancy of FGFR3 with FGFR1 and FGFR2 for maintaining the epidermal barrier. Taken together, our study demonstrates that FGFR1, FGFR2 and FGFR3 act together to maintain epidermal integrity and cutaneous homeostasis, with FGFR2 being the dominant receptor.     

Key Ecological Function Peaks at the Land–Ocean Transition Zone When Vertebrate Scavengers Concentrate on Ocean Beaches

Ecosystems - Ecotones can form hot spots of biodiversity by containing species from multiple ecosystems. Because biodiversity is often linked to ecological function, we posit that rates of key...