Carbon monoxide-releasing molecule-2 ameliorates postresuscitation myocardial dysfunction in rat via mitochondrial-mediated apoptosis pathway and the regulation of mitochondrial dynamics

Hypoxia-preconditioned bone marrow-derived mesenchymal stem cells protect neurons from cardiac arrest-induced pyroptosis

JOURNAL/nrgr/04.03/01300535-202504000-00027/figure1/v/2024-07-06T104127Z/r/image-tiff Cardiac arrest can lead to severe neurological impairment as a result of inflammation, mitochondrial dysfunction, and post-cardiopulmonary resuscitation neurological damage. Hypoxic preconditioning has been shown to improve migration and survival of bone marrow-derived mesenchymal stem cells and reduce pyroptosis after cardiac arrest, but the specific mechanisms by which hypoxia-preconditioned bone marrow-derived mesenchymal stem cells protect against brain injury after cardiac arrest are unknown. To this end, we established an in vitro co-culture model of bone marrow-derived mesenchymal stem cells and oxygen-glucose deprived primary neurons and found that hypoxic preconditioning enhanced the protective effect of bone marrow stromal stem cells against neuronal pyroptosis, possibly through inhibition of the MAPK and nuclear factor κB pathways. Subsequently, we transplanted hypoxia-preconditioned bone marrow-derived mesenchymal stem cells into the lateral ventricle after the return of spontaneous circulation in an 8-minute cardiac arrest rat model induced by asphyxia. The results showed that hypoxia-preconditioned bone marrow-derived mesenchymal stem cells significantly reduced cardiac arrest-induced neuronal pyroptosis, oxidative stress, and mitochondrial damage, whereas knockdown of the liver isoform of phosphofructokinase in bone marrow-derived mesenchymal stem cells inhibited these effects. To conclude, hypoxia-preconditioned bone marrow-derived mesenchymal stem cells offer a promising therapeutic approach for neuronal injury following cardiac arrest, and their beneficial effects are potentially associated with increased expression of the liver isoform of phosphofructokinase following hypoxic preconditioning.

The Heme Oxygenase/Biliverdin Reductase System and Its Genetic Variants in Physiology and Diseases

Heme oxygenase (HO) metabolizes heme into ferrous iron, carbon monoxide (CO), and biliverdin-IXα (BV), the latter being reduced into bilirubin-IXα (BR) by the biliverdin reductase-A (BVR). Heme oxygenase exists as two isoforms, HO-1, inducible and involved in the cell stress response, and HO-2, constitutive and committed to the physiologic turnover of heme and in the intracellular oxygen sensing. Many studies have identified genetic variants of the HO/BVR system and suggested their connection in free radical-induced diseases. The most common genetic variants include (GT)n dinucleotide length polymorphisms and single nucleotide polymorphisms. Gain-of-function mutations in the HO-1 and HO-2 genes foster the ventilator response to hypoxia and reduce the risk of coronary heart disease and age-related macular degeneration but increase the risk of neonatal jaundice, sickle cell disease, and Parkinson's disease. Conversely, loss-of-function mutations in the HO-1 gene increase the risk of type 2 diabetes mellitus, chronic obstructive pulmonary disease, and some types of cancers. Regarding BVR, the reported loss-of-function mutations increase the risk of green jaundice. Unfortunately, the physiological role of the HO/BVR system does not allow for the hypothesis gene silencing/induction strategies, but knowledge of these mutations can certainly facilitate a medical approach that enables early diagnoses and tailored treatments.

Role of gasotransmitters in necroptosis

Gasotransmitters are endogenous gaseous signaling molecules that can freely pass through cell membranes and transmit signals between cells, playing multiple roles in cell signal transduction. Due to extensive and ongoing research in this field, we have successfully identified many gasotransmitters so far, among which nitric oxide, carbon monoxide, and hydrogen sulfide are best studied. Gasotransmitters are implicated in various diseases related to necroptosis, such as cardiovascular diseases, inflammation, ischemia-reperfusion, infectious diseases, and neurological diseases. However, the mechanisms of their effects on necroptosis are not fully understood. This review focuses on endogenous gasotransmitter synthesis and metabolism and discusses their roles in necroptosis, aiming to offer new insights for the therapeutic approaches to necroptosis-associated diseases.

Epigallocatechin gallate attenuated high glucose-induced pancreatic beta cell dysfunction by modulating DRP1-mediated mitochondrial apoptosis pathways

Long-term exposure to hyperglycemic conditions leads to β-cell dysfunction, particularly mitochondrial dysfunction, and inflammatory and oxidative stress responses, which are considered the primary causes of β-cell death and the hallmarks of diabetes. Plant-active ingredients may play a key role in glycemic control. Epigallocatechin gallate (EGCG) is a characteristic catechin derived from tea that possesses anti-diabetic properties. Nonetheless, its underlying mechanisms remain elusive. Herein, the protective role of EGCG on high glucose (33 mM)-induced pancreatic beta cell dysfunction and its possible molecular mechanisms were investigated. Briefly, MIN6 cells were treated with glucose and EGCG (10 µM, 20 µM, and 40 µM) for 48 h. Our results revealed that EGCG dose-dependently restored mitochondrial membrane potential and concomitantly alleviated cell apoptosis. Mechanistically, the expression level of apoptotic protein BAX and Dynamic related protein 1 (DRP1) was significantly downregulated following EGCG treatment, whereas that of the anti-apoptotic protein BCL-2 was significantly upregulated. Taken together, EGCG alleviated high glucose-induced pancreatic beta cell dysfunction by targeting the DRP1-related mitochondrial apoptosis pathway and thus can serve as a nutritional intervention for the preservation of beta cell dysfunction in patients with type 2 diabetes mellitus.

Polymeric nano-micelle of carbon monoxide donor SMA/CORM2 ameliorates acetaminophen-induced liver injury via suppressing HMGB1/TLR4 signaling pathway

Acetaminophen (APAP) overdose-induced hepatotoxicity is the most common cause of acute liver failure. Excessive generation of reactive oxygen species (ROS) and inflammatory responses are the major causes of necrosis and/or necroptosis of the liver cells. Currently, the treatment options for APAP-induced liver injury are very limited, N-acetylcysteine (NAC) is the only approved drug to treat APAP overdose patients. It is of great necessity to develop new therapeutic strategies. In a previous study, we focused on the anti-oxidative, anti-inflammatory signal molecule carbon monoxide (CO), and developed a nano-micelle encapsulating CO donor, i.e., SMA/CORM2. Administration of SMA/CORM2 to the mice exposed to APAP significantly ameliorated the liver injury and inflammatory process, in which modulating macrophage reprogramming plays a critical role. Along this line, in this study, we investigated the potential effect of SMA/CORM2 on toll-like receptor 4 (TLR4) and high mobility group protein B1 (HMGB1) signaling pathways that are known to be closely involved in many inflammatory responses and necroptosis. In a mouse APAP-induced liver injury model, similar to the previous study, SMA/CORM2 at 10 mg/kg remarkably improved the condition of the liver after injury as evidenced by histological examination and liver function. During the process of liver injury triggered by APAP, TLR4 expression gradually increased over time, and it was significantly upregulated as early as 4 h after APAP exposure, whereas, an increase of HMGB1 was a late-stage event. Notably, SMA/CORM2 treatment suppressed significantly both TLR4 and HMGB1, consequently inhibiting the progression of inflammation and liver injury. Compared to CORM2 without SMA modification (native CORM2) of 1 mg/kg that is equivalent to 10 mg/kg of SMA/CORM2 (the amount of CORM2 in SMA/CORM2 is 10% [w/w]), SMA/CORM2 exhibited a much better therapeutic effect, indicating its superior therapeutic efficacy to native CORM2. These findings revealed that SMA/CORM2 protects against APAP-induced liver injury via mechanisms involving the suppression of TLR4 and HMGB1 signaling pathways. Taking together the results in this study and previous studies, SMA/CORM2 exhibits great therapeutic potential for APAP overdose-induced liver injury, we thus anticipate the clinical application of SMA/CORM2 for the treatment of APAP overdose, as well as other inflammatory diseases.

Cinnamaldehyde regulates mitochondrial quality against hydrogen peroxide induced apoptosis in mouse lung mesenchymal stem cells via the PINK1/Parkin signaling pathway

Background

Idiopathic pulmonary fibrosis (IPF) is a fatal respiratory disease without effective treatments. Mitochondrial dysfunction weakens the ability of mesenchymal stem cells (MSCs) to repair the distal lung epithelium, which is a probable pathogenesis of IPF. In previous research, we found that cinnamaldehyde (CA) can maintain the mitochondrial morphology of MSCs.

Methods

This present study evaluated the effect and mechanism of CA on murine lung MSCs using the hydrogen peroxide model. Antioxidant effects and mitochondrial function were determined using flow cytometry. The mRNA levels of mitochondrial dynamics and the expressions of autophagy-related proteins were also detected.

Results

CA can increase the levels of SOD, MMP and ATP, decrease the rate of ROS and apoptosis, and restore the mitochondrial structure. CA can also improve the mRNA expression of MFN1, MFN2, FIS1, DRP1, OPA1, and PGC-1α, increase the expression of LC3 II and p62 and promote the PINK1/Parkin signaling pathway. Our results demonstrated that CA can control mitochondrial quality and avoid apoptosis, which may be associated with the regulation of the PINK1/Parkin signaling pathway.