MR targeted imaging for the expression of tenascin-C in myocardial infarction in vivo

MiR-495-3p depletion contributes to myocardial ischemia/reperfusion injury in cardiomyocytes by targeting TNC

Background

Tenascin-C (TNC) has been found to abnormally express in myocardial ischemia/reperfusion injury (MI/RI), but its effect on cardiomyocytes apoptosis is unknown and is worthy of investigation.

Methods

H9C2 cells were given hypoxia/reoxygenation (H/R) treatment to obtain the replica of MI/RI in vitro. The effect of H/R on viability, apoptosis and inflammation was studied by CCK-8 assay, flow cytometry, mitochondrial membrane potential (MMP) and Ca²⁺ measurements as well as enzyme linked immunosorbent assay. We applied bioinformatics analysis and luciferase reporter assay to screened and validated TNC-targeting miR-495-3p which was then mechanistically investigated by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. With the assistance of cell transfection, rescue assays were conducted.

Results

H9C2 cells showed diminished viability, accelerated apoptosis, elevated tumour necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β), and TNC overexpression in response to H/R induction, while silencing of TNC partially reversed the effect of H/R treatment on the H9C2 cells. TNC silencing reduced Ca²⁺ level and enhanced MMP level in the H/R-stimulated cells. MiR-495-3p targeted TNC and showed a low expression in the H/R-stimulated cells. The expression of TNC was negatively regulated by miR-495-3p. Inhibition of miR-495-3p repressed viability and MMP level, and facilitated apoptosis and levels of Ca²⁺, TNF-α and IL-1β in the H/R-stimulated cells. The effect of TNC silencing and miR-495-3p depletion on H/R-induced cardiomyocyte injury was mutually reversed in vitro.

Conclusion

MiR-495-3p targeted TNC to regulate the apoptosis and inflammation of cardiomyocytes in H/R induction, which was associated with Ca²⁺ overload.

Tenascin-C expression in the lymph node pre-metastatic niche in muscle-invasive bladder cancer

BACKGROUND

Markers of stromal activation at future metastatic sites may have prognostic value and may allow clinicians to identify and abolish the pre-metastatic niche to prevent metastasis. In this study, we evaluate tenascin-C as a marker of pre-metastatic niche formation in bladder cancer patient lymph nodes.

METHODS

Tenascin-C expression in benign lymph nodes was compared between metastatic (n = 20) and non-metastatic (n = 27) patients with muscle-invasive bladder cancer. Urinary extracellular vesicle (EV) cytokine levels were measured with an antibody array to examine potential correlation with lymph node inflammation. The ability of bladder cancer EVs to activate primary bladder fibroblasts was assessed in vitro.

RESULTS

Lymph node tenascin-C expression was elevated in metastatic patients vs. non-metastatic patients, and high expression was associated with worse survival. Urinary EVs contained four cytokines that were positively correlated with lymph node tenascin-C expression. Bladder cancer EVs induced tenascin-C expression in fibroblasts in an NF-κB-dependent manner.

CONCLUSIONS

Tenascin-C expression in regional lymph nodes may be a good predictor of bladder cancer metastasis and an appropriate imaging target. It may be possible to interrupt pre-metastatic niche formation by targeting EV-borne tumour cytokines or by targeting tenascin-C directly.

Direct in vivo reprogramming with non-viral sequential targeting nanoparticles promotes cardiac regeneration

microRNA-mediated direct cardiac reprogramming, directly converts fibroblasts into induced cardiomyocyte-like cells (iCMs), which holds great promise in cardiac regeneration therapy. However, effective approaches to deliver therapeutic microRNA into cardiac fibroblasts (CFs) to induce in vivo cardiac reprogramming remain to be explored. Herein, a non-viral biomimetic system to directly reprogram CFs for cardiac regeneration after myocardial injury was developed by coating FH peptide-modified neutrophil-mimicking membranes on mesoporous silicon nanoparticles (MSNs) loaded with microRNA1, 133, 208, and 499 (miR Combo). Through utilizing the natural inflammation-homing ability of neutrophil membrane protein and FH peptide's high affinity to tenascin-C (TN-C) produced by CFs, this nanoparticle could realize sequential targeting to CFs in the injured heart and precise intracellular delivery of miRCombo, which induced reprogramming resident CFs into iCMs. In a mouse model of myocardial ischemia/reperfusion injury, intravenous injection of the nanoparticles successfully delivered miRCombo into fibroblasts and led to efficient reprogramming, resulting in improved cardiac function and attenuated fibrosis. This delivery system is minimally invasive and bio-safe, providing a proof-of-concept for biomimetic and sequential targeting nanomedicine delivery system for microRNA-mediated reprogramming therapy in multiple diseases.

Application of Magnetic Resonance Imaging Molecular Probe in the Study of Pluripotent Stem Cell-Derived Neural Stem Cells for the Treatment of Posttraumatic Paralysis of Cerebral Infarction

The feasibility and efficacy of magnetic resonance imaging molecular probe application and pluripotent stem cell-derived neural stem cell (NSC) transplantation for the treatment of hind limb paralysis in mice with cerebral infarction were studied. A model of middle cerebral artery infarction using adult mice was established to stimulate hind limb reactions. After the model was successfully established, the mice were first divided into an experimental group and a control group, with 25 mice in each group. Cultured neural cells were obtained from the cerebral cortex and hippocampus of a mouse 15 days pregnant to prepare pluripotent stem cells. Pluripotent stem cell-derived NSCs were identified by positive expression of Nestin. The experimental group was injected with 1 μL of NSC suspension through the tail vein, and the control group was injected with 1 μL of saline through the tail vein. The neurologic function of mice in each group was scored 1 day, 3 days, 7 days, 14 days, and 28 days after transplantation according to the Garcia 18 subscale. Finally, the differentiation, migration, and integration of pluripotent stem cell-derived NSCs after transplantation were observed using a magnetic resonance imaging molecular probe method. The results showed that the neurologic function scores of the ischemic transplantation group were significantly higher than those of the control group, and the results were significantly different (P < 0.05). Through research, it was found that after transplantation of pluripotent stem cell-derived NSCs, the transplanted cells migrated and differentiated around the body at 28 days and participated in angiogenesis, and the blood vessels in the infarcted area were obviously proliferated. The NSCs cultured in vitro were transplanted to the small infarction after cerebral infarction. In rats, it plays a positive role in the repair of nerve function in mice with cerebral infarction. NSCs cultured in vitro can survive, migrate, and differentiate in the brain tissue of mouse ischemic models and play a positive role in the repair of neurologic function in mice with cerebral infarction. Magnetic resonance imaging molecular probes have a good adjuvant effect on the use of pluripotent stem cell-derived NSCs to treat hind limb paralysis in mice with cerebral infarction.

Future perspectives of nanoparticle-based contrast agents for cardiac magnetic resonance in myocardial infarction

Cardiac Magnetic Resonance (CMR), thanks to high spatial resolution and absence of ionizing radiation, has been widely used in myocardial infarction (MI) assessment to evaluate cardiac structure, function, perfusion and viability. Nevertheless, it suffers from limitations in tissue and assessment of myocardial pathophysiological changes subsequent to MI. In this issue, nanoparticle-based contrast agents offer the possibility to track biological processes at cellular and molecular level underlying the various phases of MI, infarct healing and tissue repair. In this paper, first we examine the conventional CMR protocol and its findings in MI patients. Next, we looked at how nanoparticles can help in the imaging of MI and give an overview of the major approaches currently explored. Based on the presentation of successful nanoparticle applications as contrast agents (CAs) in preclinical and clinical models, we discuss promises and outstanding challenges facing the field of CMR in MI, their translational potential and clinical application.

In vivo MRI detection of atherosclerosis in ApoE-deficient mice by using tenascin-C-targeted USPIO

BACKGROUND

Atherosclerosis is the main cause of cardiovascular and cerebrovascular diseases. Non-invasive molecular imaging to detect and characterize the plaques is essential for reducing life-threatening cardiovascular events.

PURPOSE

To investigate the possibility of the anti-tenascin-C-USPIO specific probe as a molecular marker of atherosclerotic plaques detected by 7.0-T magnetic resonance imaging (MRI).

MATERIAL AND METHODS

Twenty ApoE^-/- mice fed with a high fat diet were used for detecting the aorta arch atherosclerotic plaques by 7.0-T MRI at 16 and 24 weeks. Ten mice in the targeted group were injected with anti-tenascin-C-USPIO and another ten in the control group were injected with pure USPIO (n = 5 each time point in each group). Histopathologic examination was used to evaluate the plaques and immunohistochemistry analysis was used to compare tenascin-C expression.

RESULTS

The relative signal intensity (rSI) changes of the targeted group decreased more than those of the control group (16 weeks: -15.65 ± 0.78% vs. -3.43 ± 2.57%; 24 weeks: -26.38 ± 1.54% vs. -11.12 ± 1.60%, respectively; P < 0.05). Histopathological analyses demonstrated visible atherosclerotic plaques formation and development over time from 16 weeks to 24 weeks. Tenascin-C expression of the plaques at 24 weeks was higher than that at 16 weeks (0.22 ± 0.04 vs. 0.13 ± 0.02, P < 0.05). The MR images correlated well with the progression of atherosclerotic plaques.

CONCLUSION

Tenascin-C expression increased with the progression of atherosclerosis. Anti-tenascin-C-USPIO could provide a useful molecular imaging tool for detecting and monitoring atherosclerotic plaques by MRI.