Early detection of cardiac fibrosis in diabetic mice by targeting myocardiopathy and matrix metalloproteinase 2.

Early detection of myocardial fibrosis in diabetic cardiomyopathy (DCM) has significant clinical implications for diabetes management. In this study, we identified matrix metalloproteinase 2 (MMP2) as a potential biomarker for early fibrosis detection. Based on this finding, we designed a dual-targeting nanoparticle CHP-SPIO-ab MMP2 to specifically target myocardiopathy and MMP2, enabling sensitive fibrosis detection using magnetic resonance imaging (MRI). Our results demonstrate that collagen hyperplasia (early fiber formation) begins to develop in diabetic mice at 12 weeks old, with observable fibrosis occurring at 16 weeks old. Additionally, MMP2 expression significantly up-regulates around collagen starting from 12 weeks of age. T2 MRI analysis revealed significant T2% enhancement in the hearts of 12-week-old diabetic mice following administration of the CHP-SPIO-ab MMP2 probe, indicating noninvasive detection of fiber formation. Furthermore, after fibrosis treatment, a reduction in T2% signal was observed in the hearts of 16-week-old diabetic mice. These findings were supported by Sirius red and Prussian blue staining techniques. Overall, our study presents a promising strategy for early identification of myocardial fibrosis. STATEMENT OF SIGNIFICANCE: Myocardial damage typically exhibits irreversibility, underscoring the paramount importance of early fibrosis diagnosis. However, the clinical used T1 mapping for fibrosis detection still exhibits limitations in terms of sensitivity. Therefore, it is imperative to develop highly sensitive strategies for early cardiac fibrosis detection. Here, we investigated the development of myocardial fibrosis in diabetic mice, and designed a highly sensitive probe that specifically targets cardiomyopathy and high expression of MMP2 for the early diagnosis of fibrosis. The probe enables non-invasive detection of abnormalities through MRI imaging as soon as fiber deposition appear, which can be detected earlier than T1 mapping. This advancement holds great potential for clinical diagnosis of myocardial fibrosis using cardiac magnetic resonance.

Doubling of surface oceanic meridional heat transport by non-symmetry of mesoscale eddies.

Oceanic transport of heat by ubiquitous mesoscale eddies plays a critical role in regulating climate variability and redistributing excess heat absorbed by ocean under global warming. Eddies have long been simplified as axisymmetric vortices and their influence on heat transport remains unclear. Here, we combine satellite and drifter data and show that oceanic mesoscale eddies are asymmetric and directionally-dependent, and are controlled by their self-sustaining nature and their dynamical environment. Both the direction and amplitude of eddy-induced heat fluxes are significantly influenced by eddy's asymmetry and directional dependence. When the eddy velocity field is decomposed into asymmetric and symmetric components, the eddy kinetic energy exhibits a nearly equal partition between these two components. The total eddy-induced meridional heat flux similarly doubles the heat flux induced by the symmetric components, highlighting the crucial contribution of eddy asymmetry on the magnitude of eddy-induced oceanic heat transport.

An Engineered Synthetic Receptor-Aptamer Pair for an Artificial Signal Transduction System.

Cell membrane receptors regulate cellular responses through sensing extracellular environmental signals and subsequently transducing them. Receptor engineering provides a means of directing cells to react to a designated external cue and exert programmed functions. However, rational design and precise modulation of receptor signaling activity remain challenging. Here, we report an aptamer-based signal transduction system and its applications in controlling and customizing the functions of engineered receptors. A previously reported membrane receptor-aptamer pair was used to design a synthetic receptor system that transduces cell signaling depending on exogenous aptamer input. To eliminate the cross-reactivity of the receptor with its native ligand, the extracellular domain of the receptor was engineered to ensure that the receptor was solely activated by the DNA aptamer. The present system features tunability in the signaling output level using aptamer ligands with different receptor dimerization propensities. In addition, the functional programmability of DNA aptamers enables the modular sensing of extracellular molecules without the need for genetic engineering of the receptor.

Ambient Fine Particulate Matter and Cancer: Current Evidence and Future Perspectives.

The high incidence of cancer has placed an enormous health and economic burden on countries around the world. In addition to evidence of epidemiological studies, conclusive evidence from animal experiments and mechanistic studies have also shown that morbidity and mortality of some cancers can be attributed to ambient fine particulate matter (PM2.5) exposure, especially in lung cancer. However, the underlying carcinogenetic mechanisms of PM2.5 remain unclear. Furthermore, in terms of risks of other types of cancer, both epidemiological and mechanistic evidence are more limited and scattered, and the results are also inconsistent. In order to sort out the carcinogenic effect of PM2.5, this paper reviews the association of cancers with PM2.5 based on epidemiological and biological evidence including genetic, epigenetic, and molecular mechanisms. The limitations of existing researches and the prospects for the future are also well clarified in this paper to provide insights for future studies.

The emerging roles and therapeutic potential of B cells in sepsis.

Sepsis is a life-threatening syndrome caused by anomalous host response to infection. The pathogenesis of sepsis is complex, and immune dysfunction is the central link in its occurrence and development. The sepsis immune response is not a local and transient process but a complex and continuous process involving all major cell types of innate and adaptive immunity. B cells are traditionally studied for their ability to produce antibodies in the context of mediating humoral immunity. However, over the past few years, B cells have been increasingly recognized as key modulators of adaptive and innate immunity, and they can participate in immune responses by presenting antigens, producing cytokines, and modulating other immune cells. Recently, increasing evidence links B-cell dysfunction to mechanisms of immune derangement in sepsis, which has drawn attention to the powerful properties of this unique immune cell type in sepsis. Here, we reviewed the dynamic alterations of B cells and their novel roles in animal models and patients with sepsis, and provided new perspectives for therapeutic strategies targeting B cells in sepsis.

Biocompatible Iron Oxide Nanoring-Labeled Mesenchymal Stem Cells: An Innovative Magnetothermal Approach for Cell Tracking and Targeted Stroke Therapy.

Labeling stem cells with magnetic nanoparticles is a promising technique for in vivo tracking and magnetic targeting of transplanted stem cells, which is critical for improving the therapeutic efficacy of cell therapy. However, conventional endocytic labeling with relatively poor labeling efficiency and a short labeling lifetime has hindered the implementation of these innovative enhancements in stem-cell-mediated regenerative medicine. Herein, we describe an advanced magnetothermal approach to label mesenchymal stem cells (MSCs) efficiently by local induction of heat-enhanced membrane permeability for magnetic resonance imaging (MRI) tracking and targeted therapy of stroke, where biocompatible γ-phase, ferrimagnetic vortex-domain iron oxide nanorings (γ-FVIOs) with superior magnetoresponsive properties were used as a tracer. This approach facilitates a safe and efficient labeling of γ-FVIOs as high as 150 pg of Fe per cell without affecting the MSCs proliferation and differentiation, which is 3.44-fold higher than that by endocytosis labeling. Such a high labeling efficiency not only enables the ultrasensitive magnetic resonance imaging (MRI) detection of sub-10 cells and long-term tracking of transplanted MSCs over 10 weeks but also endows transplanted MSCs with a magnetic manipulation ability in vivo. A proof-of-concept study using a rat stroke model showed that the labeled MSCs facilitated MRI tracking and magnetic targeting for efficient replacement therapy with a significantly reduced dosage of 5 × 104 transplanted cells. The findings in this study have demonstrated the great potential of the magnetothermal approach as an efficient labeling technique for future clinical usage.

Errate: Promoting Role of Long Non-Coding RNA Small Nucleolar RNA Host Gene 15 (SNHG15) in Neuronal Injury Following Ischemic Stroke via the MicroRNA-18a/CXC Chemokine Ligand 13 (CXCL13)/ERK/MEK Axis.

The figure 3D was published as figure 3E. The correct figure 3E is provided below. Reference: Tiezhu Guo, Yueting Liu, Xinliang Ren, Wei Wang, Hanrui Liu. Promoting Role of Long Non-Coding RNA Small Nucleolar RNA Host Gene 15 (SNHG15) in Neuronal Injury Following Ischemic Stroke via the MicroRNA-18a/CXC Chemokine Ligand 13 (CXCL13)/ERK/MEK Axis. Med Sci Monit 2020; 26:e923610; DOI: 10.12659/MSM.923610.

In vivo Detection of Macromolecule Free Radicals in Mouse Sepsis-Associated Encephalopathy Using a New MRI and Immunospin Trapping Strategy.

Introduction: Free radicals in oxidative stress are known to play a pathogenic role in sepsis. A major clinical challenge associated with sepsis is sepsis-associated encephalopathy (SAE). The rapid increase of free radicals in the brain promotes SAE progression. Here, macromolecule free radicals in the mouse brain were uniquely detected by immunospin trapping (IST) and magnetic resonance imaging (MRI). Methods: The new strategy uses spin trapping agent DEPMPO-biotin to capture macromolecule free radicals in lesions and form biotin-DEPMPO-radical adducts. Then, a targeting MRI probe, avidin-BSA@Gd-ESIO, was used to detect the radical adducts through the highly specific binding of avidin and biotin. The avidin-BSA@Gd-ESIO probe was synthesized and systematically characterized. The detection capability of the new strategy was evaluated in vitro and in vivo using a confocal microscope and a 7T MRI, respectively. Results: In reactive oxygen species (ROS)-induced microglial cells, the accumulation of the avidin-BSA@Gd-ESIO probe in the DEPMPO-biotin-treated group was significantly higher than that of control groups. In vivo MRI T1 signal intensities were significantly higher within the hippocampus, striatum, and medial cortex of the brain in mice with a mild or severe degree of sepsis compared with the sham control group. Histological analysis validated that the distribution of the avidin-BSA@Gd-ESIO probe in brain tissue slices was consistent with the MRI images. The fluorescence signals of ROS and avidin-BSA@Gd-ESIO probe were overlapped and visualized using immunofluorescent staining. By evaluating the T1 signal changes over time in different areas of the brain, we estimated the optimal MRI detection time to be 30 minutes after the probe administration. Discussion: This method can be applied specifically to assess the level of macromolecular free radicals in vivo in a simple and stable manner, providing a pathway for a more comprehensive understanding of the role of free radicals in SAE.

Targeted trapping of endogenous endothelial progenitor cells for myocardial ischemic injury repair through neutrophil-mediated SPIO nanoparticle-conjugated CD34 antibody delivery and imaging.

Endothelia progenitor cell (EPC)-based revascularization therapies have shown promise for the treatment of myocardial ischemic injury. However, applications and efficacy are limited by the relatively inefficient recruitment of endogenous EPCs to the ischemic area, while implantation of exogenous EPCs carries the risk of tumorigenicity. In this study, we developed a therapeutic protocol that relies on the capacity of neutrophils (NEs) to target lesions and release preloaded EPC-binding molecules for high efficiency capture. Neutrophils were loaded with superparamagnetic iron oxide nanoparticles conjugated to an antibody against the EPC surface marker CD34 (SPIO-antiCD34/NEs), and the therapeutic efficacy in ischemic mouse heart following SPIO-antiCD34/NEs injection was monitored by SPIO-enhanced magnetic resonance imaging (MRI). These SPIO-antiCD34/NEs exhibited unimpaired cell viability, superoxide generation, and chemotaxis in vitro as well as satisfactory biocompatibility in vivo. In a mouse model of acute myocardial infarction (MI), SPIO-antiCD34 accumulation could be observed 0.5 h after intravenous injection of SPIO-antiCD34/NEs. Moreover, the degree of CD133+ EPC accumulation at MI sites was three-fold higher than in control MI model mice, while ensuing microvessel density was roughly two-fold higher than controls and left ventricular ejection fraction was > 50%. Therapeutic cell biodistribution, MI site targeting, and treatment effects were confirmed by SPIO-enhanced MRI. This study offers a new strategy to improve the endogenous EPC-based myocardial ischemic injury repair through NEs mediated SPIO nanoparticle conjugated CD34 antibody delivery and imaging. STATEMENT OF SIGNIFICANCE: The efficacy of endogenous endothelial progenitor cell (EPC)-based cardiovascular repair therapy for ischemic heart damage is limited by relatively low EPC accumulation at the target site. We have developed a method to improve EPC capture by exploiting the strong targeting ability of neutrophils (NEs) to ischemic inflammatory foci and the capacity of these treated cells to release of preloaded cargo with EPC-binding affinity. Briefly, NEs were loaded with superparamagnetic iron oxide nanoparticles conjugated to an antibody against the EPC surface protein CD34 (SPIO-antiCD34). Thus, we explored sites targeting with nanocomposites cargo for non-invasive EPCs interception and therapy tracking. We demonstrate that SPIO-antiCD34 released from NEs can effectively capture endogenous EPCs and thereby promote heart revascularization and functional recovery in mice. Moreover, the entire process can be monitored by SPIO-enhanced magnetic resonance imaging including therapeutic cell biodistribution, myocardial infarction site targeting, and tissue repair.

Structural Variability of Lipoarabinomannan Modulates Innate Immune Responses within Infected Alveolar Epithelial Cells.

Mycobacterium tuberculosis (M. tb) is an intracellular pathogen persisting in phagosomes that has the ability to escape host immune surveillance causing tuberculosis (TB). Lipoarabinomannan (LAM), as a glycolipid, is one of the complex outermost components of the mycobacterial cell envelope and plays a critical role in modulating host responses during M. tb infection. Different species within the Mycobacterium genus exhibit distinct LAM structures and elicit diverse innate immune responses. However, little is known about the mechanisms. In this study, we first constructed a LAM-truncated mutant with fewer arabinofuranose (Araf) residues named M. sm-ΔM_6387 (Mycobacterium smegmatis arabinosyltransferase EmbC gene knockout strain). It exhibited some prominent cell wall defects, including tardiness of mycobacterial migration, loss of acid-fast staining, and increased cell wall permeability. Within alveolar epithelial cells (A549) infected by M. sm-ΔM_6387, the uptake rate was lower, phagosomes with bacterial degradation appeared, and microtubule-associated protein light chain 3 (LC3) recruitment was enhanced compared to wild type Mycobacteriumsmegmatis (M. smegmatis). We further confirmed that the variability in the removal capability of M. sm-ΔM_6387 resulted from host cell responses rather than the changes in the mycobacterial cell envelope. Moreover, we found that M. sm-ΔM_6387 or its glycolipid extracts significantly induced expression changes in some genes related to innate immune responses, including Toll-like receptor 2 (TLR2), class A scavenger receptor (SR-A), Rubicon, LC3, tumor necrosis factor alpha (TNF-α), Bcl-2, and Bax. Therefore, our studies suggest that nonpathogenic M. smegmatis can deposit LC3 on phagosomal membranes, and the decrease in the quantity of Araf residues for LAM molecules not only impacts mycobacterial cell wall integrity but also enhances host defense responses against the intracellular pathogens and decreases phagocytosis of host cells.

Characterization of early myocardial inflammation in ischemia-reperfusion injury.

Background: Myocardial injury may be caused by myocardial ischemia-reperfusion (IR), and salvaging such an injury is still a great challenge in clinical practice. This study comprehensively characterized the physiopathologic changes of myocardial injury after IR to explore the underlying mechanism in the early reperfusion phase with particular emphasis on early myocardial inflammation. Methods and Results: The experimental IR model was obtained by the left anterior descending artery's transient ligation of C57BL/6 mice. T2W signals of all mice showed increased signal at different IR stages. It was positively correlated with inflammatory cytokines and cells. T2W imaging by 7.0 T MRI surprisingly detected signal enhancement, but histopathology and flow cytometry did not reveal any inflammatory cells infiltration within 3 h after IR. Cardiomyocyte swelling and increased vascular permeability were observed by WGA staining and ultrastructural analysis, respectively. The 3 h IR group showed that the cardiomyocytes were severely affected with disintegrating myofilaments and mitochondria. Both VEGF and phosphorylated Src protein were markedly expressed in the 3 h IR group in comparison with the sham group, and TUNEL staining displayed little positive cells. Cleaved caspase-3 apoptin also has similar expression levels with that of the sham group. Resident macrophages had notably become M1 phenotype. The T2W signal was still elevated, and we observed that collagen deposition occurred from 1 to 7 days. Conclusions: The inflammation response during the first week after reperfusion injury gradually increase 3 h later, but the main manifestation before that was edema. This study indicated that the first 3 h may be crucial to the early rescue process for reperfusion-induced myocardial injury due to inflammatory cell infiltration absence and apoptosis.

Nongenetic control of receptor signaling dynamics using a DNA-based optochemical tool.

Optochemical tools that can modulate the activity of the target protein provide an opportunity for studying and regulating the related biological processes. Here we present a DNA-based nongenetic optochemical tool that can control the dynamics of growth factor signaling. This photo-caged mimicry of growth factor can be a promising tool for elucidating a linkage between the dynamics of signaling and the resulting biological outcomes, as well as for manipulating cellular functions and the fate of living cells.

Supramolecular Chemotherapy: Host-Guest Complexes of Heptaplatin-Cucurbit[7]uril toward Colorectal Normal and Tumor Cells.

Supramolecular chemotherapy is a strategy that is currently used to improve the therapeutic efficacy of traditional chemotherapy while mitigating side effects. Heptaplatin, a platinum chemotherapeutic antitumor drug in colorectal tumors, is traditionally used in the clinic. However, its side effects and low efficiency in killing tumors remain unresolved. Herein, a facile supramolecular chemotherapy platform on account of the host-guest chemistry between cucurbit[7]uril and the commercially available heptaplatin was studied. At pH 7.4, heptaplatin showed a strong binding to the cucurbit[7]uril nanocarrier by 1H NMR, whose Ka was (1.38 ± 0.06) × 106 M-1 by isothermal titration calorimetry (ITC). At pH 6.0 in a tumor microenvironment, overexpressed spermine can exchange competitively heptaplatin from heptaplatin-CB[7]. This supramolecular complex achieved higher antitumor activity on colorectal tumor cells and lower cytotoxicity than the drug alone on colorectal normal cells. Furthermore, the antitumor mechanisms of supramolecular complex were investigated by apoptosis, cell cycle, and spermine synthase. It was found that heptaplatin-CB[7] consumed more colorectal tumorous intracellular spermine by the spermine synthase assay (413.85 ± 0.004 pg/mL); hepataplatin-CB[7] caused early apoptosis (87.73%) of colorectal tumor cells; heptaplatin-CB[7] induced an inhibitory response in the G1 phase of the tumor cell cycle. These findings demonstrated that heptaplatin-CB[7] had higher antitumor activity toward human colorectal tumor cells but lower cytotoxicity toward human colorectal normal cells. It is expected to promote the supramolecular chemotherapy and translational development of the nanocomplex into the clinical field.

Promoting Role of Long Non-Coding RNA Small Nucleolar RNA Host Gene 15 (SNHG15) in Neuronal Injury Following Ischemic Stroke via the MicroRNA-18a/CXC Chemokine Ligand 13 (CXCL13)/ERK/MEK Axis.

BACKGROUND Long-non-coding RNA (lncRNA) SNHG15 has been reported to be an aberrantly expressed lncRNA in patients with ischemic stroke, but its role in neuronal injury following ischemic stroke remains unclear. We hypothesized that this lncRNA is associated with the pathogenesis of ischemic stroke. MATERIAL AND METHODS A mouse model of ischemic stroke was established by middle cerebral artery occlusion (MCAO). A neurogenic mouse cell line Neuro-2a (N2a) was subjected to oxygen-glucose deprivation (OGD) for in vitro experiments. Expression of SNHG15, microRNA-18a (miR-18a), and CXCL13 in mouse brain and in OGD-treated N2a cells was determined. Altered expression of SNHG15 and miR-18a was introduced to detect their roles in N2a cell viability and apoptosis. Targeting relationships between miR-18a and SNHG15 or CXCL13 were validated by luciferase assays. Cells were treated with the ERK/MEK antagonist U0126 to assess the role of the ERK/MEK signaling pathway in N2a cell growth. RESULTS SNHG15 and CXCL13 were overexpressed and miR-18a was underexpressed in MCAO-induced mice and OGD-treated N2a cells. Silencing of SNHG15 or overexpression of miR-18a promoted cell viability, while decreased cell apoptosis induced by OGD; however, subsequent disruption of the ERK/MEK signaling pathway reversed these effects. SNHG15 was found to bind to miR-18a, which could further target CXCL13. CONCLUSIONS Silencing of SNHG15 led to CXCL13 upregulation through sequestering miR-18a and the following ERK/MEK activation, thus enhancing viability while reducing apoptosis of N2a cells. SNHG15 may serve as a novel target for ischemic stroke treatment.

Effect of peptidoglycan amidase MSMEG_6281 on fatty acid metabolism in Mycobacterium smegmatis.

Mycobacterium smegmatis MSMEG_6281, a peptidoglycan (PG) amidase, is essential in maintaining cell wall integrity. To address the potential roles during the MSMEG_6281-mediated biological process, we compared proteomes from wild-type M.smegmatis and MSMEG_6281 gene knockout strain (M.sm-ΔM_6281) using LC-MS/MS analysis. Peptide analysis revealed that 851 proteins were differentially produced with at least 1.2-fold changes, including some proteins involved in fatty acid metabolism such as acyl-CoA synthase, acyl-CoA dehydrogenase, MCE-family proteins, ATP-binding cassette (ABC) transporters, and MmpL4. Some proteins related to fatty acid degradation were enriched through protein-protein interaction analysis. Therefore, proteomic data showed that a lack of MSMEG_6281 affected fatty acid metabolism. Mycobacteria can produce diverse lipid molecules ranging from single fatty acids to highly complex mycolic acids, and mycobacterial surface-exposed lipids may impact biofilm formation. In this study, we also assessed the effects of MSMEG_6281 on biofilm phenotype using semi-quantitative and morphology analysis methods. These results found that M.sm-ΔM_6281 exhibited a delayed biofilm phenotype compared to that of the wild-type M.smegmatis, and the changes were recovered when PG amidase was rescued in a ΔM_6281::Rv3717 strain. Our results demonstrated that MSMEG_6281 impacts fatty acid metabolism and further interferes with biofilm formation. These results provide a clue to study the effects of PG amidase on mycobacterial pathogenicity.

Elevated IL-6 and TNF-α Levels in Cerebrospinal Fluid of Subarachnoid Hemorrhage Patients.

The present study investigated the correlation between interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) levels in cerebrospinal fluid (CSF) and subarachnoid hemorrhage (SAH) progression. A meta-analysis was further conducted from pooled data to analyze the clinical value of IL-6 and TNF-α in SAH diagnosis. In our case-control study, a total of 57 SAH patients were assigned to two groups, CVS group (n = 27) and non-CVS group (n = 30), based on the presence of cerebral vasospasm (CVS). In addition, 65 healthy subjects were enrolled as controls. IL-6 and TNF-α levels in CSF were measured in all the study subjects by enzyme-linked immunosorbent assay (ELISA). For meta-analysis, an exhaustive literature search was conducted to identify relevant published articles and strict inclusion and exclusion criteria were applied to select studies for the present meta-analysis. Data extracted from these studies was analyzed using STATA 12.0 software. IL-6 and TNF-α levels in CSF of SAH patients were markedly higher than those of healthy controls (all P < 0.001). Further, CVS patients showed elevated IL-6 and TNF-α levels in CSF compared to non-CVS patients (all P < 0.001). The increase in IL-6 and TNF-α levels in CSF correlated with the increasing disease severity, based on Hunt-Hess grade, in SAH patients (all P < 0.05). Our meta-analysis also confirmed that IL-6 and TNF-α CSF levels were markedly higher in SAH patients compared to healthy controls (all P < 0.001). Ethnicity-stratified analysis showed that both IL-6 and TNF-α CSF levels were elevated in Asian SAH patients, compared to their healthy counterparts (all P < 0.05). The TNF-α CSF levels were significantly higher in Caucasian SAH patients (P < 0.001), but the IL-6 CSF levels showed no such differences compared to the healthy controls (P = 0.219). Subgroup analysis based on the presence of CVS showed that both IL-6 and TNF-α CSF levels were markedly higher in CVS patients than those in non-CVS patients (all P < 0.05). Our results provide strong evidence that IL-6 and TNF-α CSF levels are elevated in SAH patients and may participate in SAH development. Thus, these two cytokines could be important biomarkers for early diagnosis and disease monitoring in SAH patients.