Multi-organ Immune-Related Adverse Event Is a Risk Factor of Immune Checkpoint Inhibitor-Associated Myocarditis in Cancer Patients: A Multi-center Study.

Background and Objective: Immune checkpoint inhibitor (ICI)-associated myocarditis is a fatal immune-related adverse events (irAEs), which is prone to affecting multiple organ systems. Multi-organ irAEs have not been fully studied in ICI-associated myocarditis. Therefore, we aimed to explore the impact of multi-organ irAEs on ICI myocarditis in terms of clinical features, treatment, and prognosis. Methods: This was a retrospective study. The clinical data of ICI myocarditis patients were collected from 6 hospitals in China. The risk factors and characteristics of pure myocarditis and multi-organ irAEs were analyzed. The overall survival (OS) after myocarditis was analyzed and univariate and multivariate regression analysis were performed. Results: A total of 46 patients were analyzed in this study. Multi-organ irAEs were common (30/46, 65.2%) and prone to severe heart failure. The severe myocarditis was observed in 32 patients (69.6%). When myocarditis occurred, neutrophil to lymphocyte ratio, C-reactive protein, lactate dehydrogenase, interleukin (IL)-6, IL-10, creatine kinase, MB isoenzyme of creatine kinase, and brain natriuretic peptide increased from baseline, but absolute lymphocyte count decreased. Thymoma (B2/B3) was a risk factor for multi-organ irAEs. Heart failure and myocarditis were more severe in patients with multi-organ irAEs and require early corticosteroid therapy (<24 hours). Univariate analysis showed that age ≥ 60 years, myocarditis (grade 3-4), heart failure (grade 3-4), multi-organ irAEs, and severe myocarditis were associated with OS after myocarditis. After adjusting for other factors, heart failure (grade 3-4) was an independent risk factor for immune-related myocarditis (HR: 6.655, 95% CI: 1.539-28.770, p=0.011). Conclusion: Patients with ICI-associated myocarditis had multi-organ irAEs with a high incidence of severe myocarditis, mortality, and poor prognosis. Thymoma was prone to those patients with multiple organs involvement. Patients could benefit from early corticosteroid intervention. Heart failure (grade 3-4) was an independent risk factor for OS after myocarditis.

LncRNA Chaer Prevents Cardiomyocyte Apoptosis From Acute Myocardial Infarction Through AMPK Activation.

Long non-coding RNA (lncRNA) is widely reported to be involved in cardiac (patho)physiology. Acute myocardial infarction, in which cardiomyocyte apoptosis plays an important role, is a life-threatening disease. Here, we report the lncRNA Chaer that is anti-apoptotic in cardiomyocytes during Acute myocardial infarction. Importantly, lncRNA Chaer is significantly downregulated in both oxygen-glucose deprivation (oxygen-glucose deprivation)-treated cardiomyocytes in vitro and AMI heart. In vitro, overexpression of lncRNA Chaer with adeno virus reduces cardiomyocyte apoptosis induced by OGD-treated while silencing of lncRNA Chaer increases cardiomyocyte apoptosis instead. In vivo, forced expression of lncRNA Chaer with AAV9 attenuates cardiac apoptosis, reduces infarction area and improves mice heart function in AMI. Interestingly, overexpression of lncRNA Chaer promotes the phosphorylation of AMPK, and AMPK inhibitor Compound C reverses the overexpression of lncRNA Chaer effect of reducing cardiomyocyte apoptosis under OGD-treatment. In summary, we identify the novel ability of lncRNA Chaer in regulating cardiomyocyte apoptosis by promoting phosphorylation of AMPK in AMI.

Deciphering the in vivo Dynamic Proteomics of Mesenchymal Stem Cells in Critical Limb Ischemia.

OBJECTIVE: Regenerative therapy using mesenchymal stem cells (MSC) is a promising therapeutic method for critical limb ischemia (CLI). To understand how the cells are involved in the regenerative process of limb ischemia locally, we proposed a metabolic protein labeling method to label cell proteomes in situ and then decipher the proteome dynamics of MSCs in ischemic hind limb. METHODS AND RESULTS: In this study, we overexpressed mutant methionyl-tRNA synthetase (MetRS), which could utilize azidonorleucine (ANL) instead of methionine (Met) during protein synthesis in MSCs. Fluorescent non-canonical amino-acid tagging (FUNCAT) was performed to detect the utilization of ANL in mutant MSCs. Mice with hindlimb ischemia (HLI) or Sham surgery were treated with MetRSmut MSCs or PBS, followed by i.p. administration of ANL at days 0, 2 6, and 13 after surgery. FUNCAT was also performed in hindlimb tissue sections to demonstrate the incorporation of ANL in transplanted cells in situ. At days 1, 3, 7, and 14 after the surgery, laser doppler imaging were performed to detect the blood reperfusion of ischemic limbs. Ischemic tissues were also collected at these four time points for histological analysis including HE staining and vessel staining, and processed for click reaction based protein enrichment followed by mass spectrometry and bioinformatics analysis. The MetRSmut MSCs showed strong green signal in cell culture and in HLI muscles as well, indicating efficient incorporation of ANL in nascent protein synthesis. By 14 days post-treatment, MSCs significantly increased blood reperfusion and vessel density, while reducing inflammation in HLI model compared to PBS. Proteins enriched by click reaction were distinctive in the HLI group vs. the Sham group. 34, 31, 49, and 26 proteins were significantly up-regulated whereas 28, 32, 62, and 27 proteins were significantly down-regulated in HLI vs. Sham at days 1, 3, 7, and 14, respectively. The differentially expressed proteins were more pronounced in the pathways of apoptosis and energy metabolism. CONCLUSION: In conclusion, mutant MetRS allows efficient and specific identification of dynamic cell proteomics in situ, which reflect the functions and adaptive changes of MSCs that may be leveraged to understand and improve stem cell therapy in critical limb ischemia.

Analysis of mesenchymal stem cell proteomes in situ in the ischemic heart.

Rationale: Cell therapy for myocardial infarction is promising but largely unsuccessful in part due to a lack of mechanistic understanding. Techniques enabling identification of stem cell-specific proteomes in situ in the injured heart may shed light on how the administered cells respond to the injured microenvironment and exert reparative effects. Objective: To identify the proteomes of the transplanted mesenchymal stem cells (MSCs) in the infarcted myocardium, we sought to target a mutant methionyl-tRNA synthetase (MetRSL274G) in MSCs, which charges azidonorleucine (ANL), a methionine analogue and non-canonical amino acid, to tRNA and subsequently to nascent proteins, permitting isolation of ANL-labeled MSC proteomes from ischemic hearts by ANL-alkyne based click reaction. Methods and Results: Murine MSCs were transduced with lentivirus MetRSL274G and supplemented with ANL; the ANL-tagged nascent proteins were visualized by bio-orthogonal non-canonical amino-acid tagging, spanning all molecular weights and by fluorescent non-canonical amino-acid tagging, displaying strong fluorescent signal. Then, the MetRSL274G-transduced MSCs were administered to the infarcted or Sham heart in mice receiving ANL treatment. The MSC proteomes were isolated from the left ventricular protein lysates by click reaction at days 1, 3, and 7 after cell administration, identified by LC/MS. Among all identified proteins (in Sham and MI hearts, three time-points each), 648 were shared by all 6 groups, accounting for 82±5% of total proteins in each group, and enriched under mitochondrion, extracellular exosomes, oxidation-reduction process and poly(A) RNA binding. Notably, 26, 110 and 65 proteins were significantly up-regulated and 11, 28 and 19 proteins were down-regulated in the infarcted vs. Sham heart at the three time-points, respectively; these proteins are pronounced in the GO terms of extracellular matrix organization, response to stress and regulation of apoptotic process and in the KEGG pathways of complements and coagulation cascades, apoptosis, and regulators of actin cytoskeleton. Conclusions: MetRSL274G expression allows successful identification of MSC-specific nascent proteins in the infarcted hearts, which reflect the functional states, adaptive response, and reparative effects of MSCs that may be leveraged to improve cardiac repair.

Case Report: Fatal Multiorgan Failure and Heterochronous Pneumonitis Following Pembrolizumab Treatment in a Patient With Large-Cell Neuroendocrine Carcinoma of Lung.

Immune checkpoint inhibitors have radically changed the landscape of antitumor therapies in several malignancies. Despite the long-term efficacy, severe immune-related adverse events (irAEs) were not uncommon. However, fatal simultaneous multiorgan failure was rare. Here, we described a patient who developed multiorgan failure, including fulminant myocarditis, myasthenia gravis crisis, hepatic dysfunction, and delayed pneumonitis after pembrolizumab therapy for lung large-cell neuroendocrine carcinoma. After failure of high-dose steroid treatment, implantation of cardiac pacemaker combined with high-dose steroids successfully controlled myocarditis caused by immune checkpoint inhibitors (ICIs). Delayed pneumonitis occurred unexpectedly, and it was treated successfully with steroids. With wild adoption of ICIs in clinical practice, investigations for predictive markers of irAEs are warranted, and more successful treatment strategies are worth sharing.

MicroRNA expression profile and functional analysis reveal their roles in contact inhibition and its disruption switch of rat vascular smooth muscle cells.

Contact inhibition and its disruption of vascular smooth muscle cells (VSMCs) are important cellular events in vascular diseases. But the underlying molecular mechanisms are unclear. In this study we investigated the roles of microRNAs (miRNAs) in the contact inhibition and its disruption of VSMCs and the molecular mechanisms involved. Rat VSMCs were seeded at 30% or 90% confluence. MiRNA expression profiles in contact-inhibited confluent VSMCs (90% confluence) and non-contact-inhibited low-density VSMCs (30% confluence) were determined. We found that multiple miRNAs were differentially expressed between the two groups. Among them, miR-145 was significantly increased in contact-inhibited VSMCs. Serum could disrupt the contact inhibition as shown by the elicited proliferation of confluent VSMCs. The contact inhibition disruption accompanied with a down-regulation of miR-145. Serum-induced contact inhibition disruption of VSMCs was blocked by overexpression of miR-145. Moreover, downregulation of miR-145 was sufficient to disrupt the contact inhibition of VSMCs. The downregulation of miR-145 in serum-induced contact inhibition disruption was related to the activation PI3-kinase/Akt pathway, which was blocked by the PI3-kinase inhibitor LY294002. KLF5, a target gene of miR-145, was identified to be involved in miR-145-mediated effect on VSMC contact inhibition disruption, as it could be inhibited by knockdown of KLF5. In summary, our results show that multiple miRNAs are differentially expressed in contact-inhibited VSMCs and in non-contact-inhibited VSMCs. Among them, miR-145 is a critical gene in contact inhibition and its disruption of VSMCs. PI3-kinase/Akt/miR-145/KLF5 is a critical signaling pathway in serum-induced contact inhibition disruption. Targeting of miRNAs related to the contact inhibition of VSMCs may represent a novel therapeutic approach for vascular diseases.

A Natural Model of Mouse Cardiac Myocyte Senescence.

Many cardiac aging studies are performed on mice first and then, due to difficulty in mouse cardiomyocyte culture, applied the rat neonatal cardiomyocytes to further determine the mechanisms in vitro. Now, the technological challenge of mouse cardiomyocyte culture has been overcome and there is an increasing need for the senescence models of mouse cardiomyocytes. In this study, we have demonstrated that the senescence of mouse cardiomyocytes occurred with the extended culture time as shown by the increased ß-galactosidase staining, increased p53 expression, decreased telomere activity, shorted telomere length, increased production of ROS, increased cell apoptosis, and impaired mitochondrial ΔΨm. These senescent responses shared similar results in aged mouse heart tissues in vivo. In summary, we have established and characterized a novel senescence model of mouse cardiomyocytes induced by the extended culture time in vitro. The cell model could be useful for the increased cardiac aging studies worldwide.

The functional changes of the perivascular adipose tissue in spontaneously hypertensive rats and the effects of atorvastatin therapy.

The aim of this study was to examine the function of perivascular adiposa tissue (PVAT) on vascular relaxation response in spontaneously hypertensive rats (SHR) and the modulatory effects of the atorvastatin therapy on the PVAT functions. We investigated the mechanisms of the perivascular adipocyte-derived relaxation factor (PVRF) by using isolated rat's aortic rings and isometric contraction measurements. We found that contraction of the thoracic aorta induced by phenylephrine was significantly attenuated in the presence of PVAT from normotensive Wistar-Kyoto rats (WKY group) or the spontaneously hypertensive rats treated with atorvastatin (SHR-A group, atorvastatin 50mg/kg/day), whereas this effect was not observed in the thoracic aortic rings from the control SHR (SHR group). Transferring the solution incubated with PVAT-intact thoracic aorta to PVAT-free thoracic aorta, it induced a remarkable relaxation response in the WKY but not in the control SHR. Tetraethylammoniumchloride (TEA) could block the above relaxation. It was also shown that the PVRF function was likely, depending on the extracellular [Ca(2+)]; the anti-contractile effect of PVAT could be reduced by the inhibitor of the adenosine triphosphate (ATP)-dependent potassium channels, glibenclamide, and could be reduced by the inhibitor of cyclooxygenase by indomethacin. We thus infer that the PVAT function was distorted in hypertension rats, and the lipid-lowering treatment with atorvastatin could restore the PVAT function. The function of the PVRF may involve the Ca(2+)-activated potassium channels, the ATP-dependent potassium channels in vascular smooth muscle cell (SMC), and the release of PVRF from PVAT may involve prostaglandins (PGs) and the calcium metabolism. These results provide an insight into the pathological mechanisms of hypertension development, and indicate that the PVAT may be a potential new target for the hypertensive therapy.