Automated Comprehensive CT Assessment of the Risk of Diabetes and Associated Cardiometabolic Conditions.

Background CT performed for various clinical indications has the potential to predict cardiometabolic diseases. However, the predictive ability of individual CT parameters remains underexplored. Purpose To evaluate the ability of automated CT-derived markers to predict diabetes and associated cardiometabolic comorbidities. Materials and Methods This retrospective study included Korean adults (age ≥ 25 years) who underwent health screening with fluorine 18 fluorodeoxyglucose PET/CT between January 2012 and December 2015. Fully automated CT markers included visceral and subcutaneous fat, muscle, bone density, liver fat, all normalized to height (in meters squared), and aortic calcification. Predictive performance was assessed with area under the receiver operating characteristic curve (AUC) and Harrell C-index in the cross-sectional and survival analyses, respectively. Results The cross-sectional and cohort analyses included 32166 (mean age, 45 years ± 6 [SD], 28833 men) and 27 298 adults (mean age, 44 years ± 5 [SD], 24 820 men), respectively. Diabetes prevalence and incidence was 6% at baseline and 9% during the 7.3-year median follow-up, respectively. Visceral fat index showed the highest predictive performance for prevalent and incident diabetes, yielding AUC of 0.70 (95% CI: 0.68, 0.71) for men and 0.82 (95% CI: 0.78, 0.85) for women and C-index of 0.68 (95% CI: 0.67, 0.69) for men and 0.82 (95% CI: 0.77, 0.86) for women, respectively. Combining visceral fat, muscle area, liver fat fraction, and aortic calcification improved predictive performance, yielding C-indexes of 0.69 (95% CI: 0.68, 0.71) for men and 0.83 (95% CI: 0.78, 0.87) for women. The AUC for visceral fat index in identifying metabolic syndrome was 0.81 (95% CI: 0.80, 0.81) for men and 0.90 (95% CI: 0.88, 0.91) for women. CT-derived markers also identified US-diagnosed fatty liver, coronary artery calcium scores greater than 100, sarcopenia, and osteoporosis, with AUCs ranging from 0.80 to 0.95. Conclusion Automated multiorgan CT analysis identified individuals at high risk of diabetes and other cardiometabolic comorbidities. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Pickhardt in this issue.

Insights into Actin Isoform-Specific Interactions with Myosin via Computational Analysis.

Actin, which plays a crucial role in cellular structure and function, interacts with various binding proteins, notably myosin. In mammals, actin is composed of six isoforms that exhibit high levels of sequence conservation and structural similarity overall. As a result, the selection of actin isoforms was considered unimportant in structural studies of their binding with myosin. However, recent high-resolution structural research discovered subtle structural differences in the N-terminus of actin isoforms, suggesting the possibility that each actin isoform may engage in specific interactions with myosin isoforms. In this study, we aimed to explore this possibility, particularly by understanding the influence of different actin isoforms on the interaction with myosin 7A. First, we compared the reported actomyosin structures utilizing the same type of actin isoforms as the high-resolution filamentous skeletal α-actin (3.5 Å) structure elucidated using cryo-EM. Through this comparison, we confirmed that the diversity of myosin isoforms leads to differences in interaction with the actin N-terminus, and that loop 2 of the myosin actin-binding sites directly interacts with the actin N-terminus. Subsequently, with the aid of multiple sequence alignment, we observed significant variations in the length of loop 2 across different myosin isoforms. We predicted that these length differences in loop 2 would likely result in structural variations that would affect the interaction with the actin N-terminus. For myosin 7A, loop 2 was found to be very short, and protein complex predictions using skeletal α-actin confirmed an interaction between loop 2 and the actin N-terminus. The prediction indicated that the positively charged residues present in loop 2 electrostatically interact with the acidic patch residues D24 and D25 of actin subdomain 1, whereas interaction with the actin N-terminus beyond this was not observed. Additionally, analyses of the actomyosin-7A prediction models generated using various actin isoforms consistently yielded the same results regardless of the type of actin isoform employed. The results of this study suggest that the subtle structural differences in the N-terminus of actin isoforms are unlikely to influence the binding structure with short loop 2 myosin 7A. Our findings are expected to provide a deeper understanding for future high-resolution structural binding studies of actin and myosin.

Sequence Alignment-Based Prediction of Myosin 7A: Structural Implications and Protein Interactions.

Myosin, a superfamily of motor proteins, obtain the energy they require for movement from ATP hydrolysis to perform various functions by binding to actin filaments. Extensive studies have clarified the diverse functions performed by the different isoforms of myosin. However, the unavailability of resolved structures has made it difficult to understand the way in which their mechanochemical cycle and structural diversity give rise to distinct functional properties. With this study, we seek to further our understanding of the structural organization of the myosin 7A motor domain by modeling the tertiary structure of myosin 7A based on its primary sequence. Multiple sequence alignment and a comparison of the models of different myosin isoforms and myosin 7A not only enabled us to identify highly conserved nucleotide binding sites but also to predict actin binding sites. In addition, the actomyosin-7A complex was predicted from the protein-protein interaction model, from which the core interface sites of actin and the myosin 7A motor domain were defined. Finally, sequence alignment and the comparison of models were used to suggest the possibility of a pliant region existing between the converter domain and lever arm of myosin 7A. The results of this study provide insights into the structure of myosin 7A that could serve as a framework for higher resolution studies in future.

Optimizing protein crosslinking control: Synergistic quenching effects of glycine, histidine, and lysine on glutaraldehyde reactions.

Glutaraldehyde (GA) is a protein crosslinker widely used in biochemical and pharmaceutical research because it can rapidly stabilize and immobilize substrates via amine group interactions. However, controlling GA crosslinking is challenging owing to its swift reactivity and the influence of various solution conditions, such as pH and concentrations of the substrate and crosslinker. Although extensive research has focused on GA cross-linking mechanisms, studies on quenching, which is critical for preventing non-specific aggregation during prolonged storage, remain sparse. This study examines the quenching efficiency of a combined amino acid mixture of glycine, histidine, and lysine, which are commonly used as individual quenchers. Our findings, confirmed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis, demonstrate that this amino acid blend offers superior quenching compared to single amino acids, enhancing quenching activity across a wide pH spectrum. These results provide a novel approach for mitigating the high reactivity of GA with implications for improving sample preservation and stabilization in a range of biochemical applications, including microscopy and cell fixation.

Targeting the NTF2-like domain of G3BP1: Novel modulators of intracellular granule dynamics.

Stress granule (SG) is a temporary cellular structure that plays a crucial role in the regulation of mRNA and protein sequestration during various cellular stress conditions. SG enables cells to cope with stress more effectively, conserving vital energy and resources. Focusing on the NTF2-like domain of G3BP1, a key protein in SG dynamics, we explore to identify and characterize novel small molecules involved in SG modulation without external stressors. Through in silico molecular docking approach to simulate the interaction between various compounds and the NTF2-like domain of G3BP1, we identified three compounds as potential candidates that could bind to the NTF2-like domain of G3BP1. Subsequent immunofluorescence experiments demonstrated that these compounds induce the formation of SG-like, G3BP1-positive granules. Importantly, the granule formation by these compounds occurs independent from the phosphorylation of eIF2α, a common mechanism in SG formation, suggesting that it might offer a new strategy for influencing SG dynamics implicated in various diseases.

A simple and rapid preparation of smooth muscle myosin 2 for the electron microscopic analysis.

There has been an increase in the demand for purified protein as a result of recent developments in the structural biology of myosin 2. Although promising, current practices in myosin purification are usually time-consuming and cumbersome. The reported increased actin to myosin ratio in smooth muscles adds to the complexity of the purification process. Present study outlines a streamlined approach to isolate smooth muscle myosin 2 molecules from actomyosin suspension of chicken gizzard tissues. The procedure entails treating actomyosin for a brief period with actin-binding peptide phalloidin, followed by co-sedimentation and short column size exclusion chromatography. Typical myosin molecule with heavy and light chains and approximately 95% purity was examined using gel electrophoresis. Negative staining electron microscopy and image processing showed intact 10S myosin 2 molecules, proving that phalloidin is effective at eliminating majority of actin in the form of F-actin without dramatic alteration in the structure of myosin. The entire purification discussed here can be completed in a few hours, and further analysis can be done the same day. Thus, by offering quick and fresh supplies of native myosin molecules suited for structural research, specially cryo-electron microscopy, this innovative approach can be adapted to get around the drawbacks of time-intensive myosin purifying processes.

Facet-Controlled Growth of Hydroxyapatite for Effectively Removing Pb from Aqueous Solutions.

To address the growing concerns regarding severe water pollution, effective and environmentally friendly adsorbents must be identified. In this study, we prepared hydroxyapatite (HAp, Ca10(PO4)6(OH)2) as an eco-friendly absorbent via simple precipitation and obtained rod- (r-HAp) and plate-shaped HAp (p-HAp). The approach to obtaining p-HAp involved a low pH titration rate, promoting growth along the c-axis due to the adsorption of OH- on the (110) facet. Conversely, r-HAp was obtained by maintaining a high concentration of OH- during the initial stage through rapid pH titration, leading to a stronger restrictive effect on the growth of positively charged a(b)-planes. p-HAp demonstrated superior adsorption capacity, removing Pb through dissolution and recrystallization, achieving an impressive 625 mg/g within a 60 min reaction time compared to r-HAp. Our findings afford insights into the Pb removal mechanisms of HAp with different morphologies and can aid in the development of water purification strategies against heavy metal contamination.

HDAC6-MYCN-CXCL3 axis mediates allergic inflammation and is necessary for allergic inflammation-promoted cellular interactions.

Histone deacetylase 6 (HDAC6) has been shown to play an important role in allergic inflammation. This study hypothesized that novel downstream targets of HDAC6 would mediate allergic inflammation. Experiments employing HDAC6 knock out C57BL/6 mice showed that HDAC6 mediated passive cutaneous anaphylaxis (PCA) and passive systemic anaphylaxis (PSA). Antigen stimulation increased expression of N-myc (MYCN) and CXCL3 in an HDAC6-dependent manner in the bone marrow-derived mast cells. MYCN and CXCL3 were necessary for both PCA and PSA. The role of early growth response 3 (EGR3) in the regulation of HDAC6 expression has been reported. ChIP assays showed EGR3 as a direct regulator of MYCN. miR-34a-5p was predicted to be a negative regulator of MYCN. Luciferase activity assays showed miR-34a-5p as a direct regulator of MYCN. miR-34a-5p mimic negatively regulated PCA and PSA. MYCN decreased miR-34a-5p expression in antigen-stimulated rat basophilic leukemia cells (RBL2H3). MYCN was shown to bind to the promoter sequence of CXCL3. In an IgE-independent manner, recombinant CXCL3 protein increased expression of HDAC6, MYCN, and ß-hexosaminidase activity in RBL2H3 cells. Mouse recombinant CXCL3 protein enhanced the angiogenic potential of the culture medium of RBL2H3. CXCL3 was necessary for the enhanced angiogenic potential of the culture medium of antigen-stimulated RBL2H3. The culture medium of RBL2H3 was able to induce M2 macrophage polarization in a CXCL3-dependent manner. Recombinant CXCL3 protein also increased the expression of markers of M2 macrophage. Thus, the identification of the novel role of HDAC6-MYCN-CXCL3 axis can help better understand the pathogenesis of anaphylaxis.