Stress-responsive heme oxygenase-1 isoenzyme participates in Toll-like receptor 4-induced inflammation during brain ischemia

The severity of COVID-19 in hypertensive patients is associated with mirSNPs in the 3' UTR of ACE2 that associate with miR-3658: In silico and in vitro studies

The SARS-CoV-2 virus targets the antigen converting enzyme 2 (ACE2) receptor, thus resulting in elevated morbidity and an increased risk of severe and fatal COVID-19 infection in individuals with hypertension and diabetes mellitus.

Objectives

This study aimed to identify the association between increased susceptibility and severity in order to evaluate their impact in hypertensive COVID-19 patients using in vitro and in silico models.

Methods

We identified 80 miRNA binding sites on ACE2 (for different miRNAs) as well as various 30 SNPs in the miRNA binding sites of the 3' untranslated region (3' UTR) in the ACE2 gene using different online software and tools. From August 2020 to August 2021, a total of 200 nasopharyngeal/mouth swabs samples were collected from Multan, Pakistan. In order to quantify the cDNA of ACE2 and miR-3658 genes, we used Rotor Gene qRT-PCR on hypertensive patients with COVID-19 as well as healthy controls.

Results

Interestingly, the binding site of miR-3658 corresponding to the 3' UTR of ACE2 featured three SNPs (rs1457913029, C>T; rs960535757, A>C, G; rs1423809569, C>T), and its genomic sequence featured a single SNP (rs1024225815, C>T) with the same nucleotide variation (rs1457913029, C>T) which potentially increases the severity of COVID-19. Similarly, three other SNPs (rs1557852115, C>G; rs770335293, A>G; rs1024225815, C>T) were also found on the first binding site positions of miR-3658. Our in vitro study found that ACE2 gene expression had an effect on miR-3658 in COVID-19 patients who also had hypertension. In both cases, our analysis demonstrated that the in silico model captured the same biological mechanisms as the in vitro system.

Conclusion

The identified SNPs could represent potential informative signatures owing to their position in the splicing site of the ACE2 gene.

Crosstalk Between Autophagy and Inflammation in Chronic Cerebral Ischaemia

Chronic cerebral ischaemia (CCI) is a high-incidence cardiovascular and cerebrovascular disease that is very common in clinical practice. Although many pathogenic mechanisms have been explored, there is still great controversy among neuroscientists regarding the pathogenesis of CCI. Therefore, it is important to elucidate the mechanisms of CCI occurrence and progression for the prevention and treatment of ischaemic cerebrovascular disorders. Autophagy and inflammation play vital roles in CCI, but the relationship between these two processes in this disease remains unknown. Here, we review the progression and discuss the functions, actions and pathways of autophagy and inflammation in CCI, including a comprehensive view of the transition from acute disease to CCI through ischaemic repair mechanisms. This review may provide a reference for future research and treatment of CCI. Schematic diagram of the interplay between autophagy and inflammation in CCI. CCI lead to serious, life-threatening complications. This review summarizes two factors in CCI, including autophagy and inflammation, which have been focused for the mechanisms of CCI. In short, the possible points of intersection are shown in the illustration. CCI, Chronic cerebral ischaemia; ER stress, Endoplasmic reticulum stress; ROS, Reactive oxygen species.

Upregulation of hemeoxygenase enzymes HO-1 and HO-2 following ischemia-reperfusion injury in connection with experimental cardiac arrest and cardiopulmonary resuscitation: Neuroprotective effects of methylene blue

Oxidative stress plays an important role in neuronal injuries after cardiac arrest. Increased production of carbon monoxide (CO) by the enzyme hemeoxygenase (HO) in the brain is induced by the oxidative stress. HO is present in the CNS in two isoforms, namely the inducible HO-1 and the constitutive HO-2. Elevated levels of serum HO-1 occurs in cardiac arrest patients and upregulation of HO-1 in cardiac arrest is seen in the neurons. However, the role of HO-2 in cardiac arrest is not well known. In this review involvement of HO-1 and HO-2 enzymes in the porcine brain following cardiac arrest and resuscitation is discussed based on our own observations. In addition, neuroprotective role of methylene blue- an antioxidant dye on alterations in HO under in cardiac arrest is also presented. The biochemical findings of HO-1 and HO-2 enzymes using ELISA were further confirmed by immunocytochemical approach to localize selective regional alterations in cardiac arrest. Our observations are the first to show that cardiac arrest followed by successful cardiopulmonary resuscitation results in significant alteration in cerebral concentrations of HO-1 and HO-2 levels indicating a prominent role of CO in brain pathology and methylene blue during CPR followed by induced hypothermia leading to superior neuroprotection after return of spontaneous circulation (ROSC), not reported earlier.

SNPs at 3'UTR of APOL1 and miR-6741-3p target sites associated with kidney diseases more susceptible to SARS-COV-2 infection: in silco and in vitro studies

Acute Kidney Injury (AKI) is a common manifestation of COVID-19 and several cases have been reported in the setting of the high-risk APOL1 genotype (common genetic variants). This increases the likelihood that African American people with the high-risk genotype APOL1 are at increased risk for kidney disease in the COVID-19 environment. Single-nucleotide polymorphisms (SNPs) are found in various microRNAs (miRNAs) and target genes change the miRNA activity that leads to different diseases. Evidence has shown that SNPs increase/decrease the effectiveness of the interaction between miRNAs and disease-related target genes. The aim of this study is not only to identify miRSNPs on the APOL1 gene and SNPs in miRNA genes targeting 3′UTR but also to evaluate the effect of these gene variations in kidney patients and their association with SARS-COV-2 infection. In 3′UTR of the APOL1 gene, we detected 96 miRNA binding sites and 35 different SNPs with 10 different online software in the binding sites of the miRNA (in silico). Also we studied gene expression of patients and control samples by using qRT-PCR (in vitro). In silico study, the binding site of miR-6741-3p on APOL1 has two SNPs (rs1288875001, G > C; rs1452517383, A > C) on APOL1 3′UTR, and its genomic sequence is the same nucleotide as rs1288875001. Similarly, two other SNPs (rs1142591, T > A; rs376326225, G > A) were identified in the binding sites of miR-6741-3p at the first position. Here, the miRSNP (rs1288875001) in APOL1 3′UTR and SNP (rs376326225) in the miR-6741-3p genomic sequence are cross-matched in the same binding region. In vitro study, the relative expression levels were calculated by the 2^−ΔΔCt method & Mann–Whitney U test. The expression of APOL1 gene was different in chronic kidney patients along with COVID-19. By these results, APOL1 expression was found lower in patients than healthy (p < 0.05) in kidney patients along with COVID-19. In addition, miR-6741-3p targets many APOL1-related genes (TLR7, SLC6A19, IL-6,10,18, chemokine (C–C motif) ligand 5, SWT1, NFYB, BRF1, HES2, NFYB, MED12L, MAFG, GTF2H5, TRAF3, angiotensin II receptor-associated protein, PRSS23) by evaluating online software in the binding sites of the miR-6741-3p. miR-6741-3p has not previously shown any association with kidney diseases and SARS-COV-2 infection. It assures that APOL1 can have a significant consequence in kidney-associated diseases by different pathways. Henceforth, this study represents and demonstrates an effective association between miR-6741-3p and kidney diseases, i.e., collapsing glomerulopathy, chronic kidney disease (CKD), acute kidney injury (AKI), and tubulointerstitial lesions susceptibility to SARS-COV-2 infection via in silico and in vitro exploration and recommended to have better insight.

Exploring the mechanism of Yizhi Tongmai decoction in the treatment of vascular dementia through network pharmacology and molecular docking

BACKGROUND

Vascular dementia (VaD) is a degenerative cerebrovascular disease that leads to progressive decline of patients' cognitive ability and memory. Yizhi Tongmai (YZTM) decoction is an empirical prescription first formulated by Professor Guomin Si. Our previous experiments proved the effectiveness of this prescription in the treatment of VaD. In this study, we aimed to use network pharmacology and molecular docking technology to systematically explain the potential anti-VaD mechanism of YZTM.

METHODS

We identified the core compounds of YZTM and their potential targets through the TCMSP, BATMAN, and SwissTargetPrediction databases. Then, we identified the molecular targets of YZTM in VaD using the Online Mendelian Inheritance in Man and GeneCards databases. The common targets of YZTM and VaD were screened out, and then the pathways of these target genes were analyzed using the Database for Annotation, Visualization and Integrated Discovery v6.8. Molecular docking was used to verify the relationship between the core compounds and proteins.

RESULTS

Through network pharmacology analysis, we discovered that the 5 core compounds in YZTM exert an anti-VaD effect. The potential mechanism of YZTM anti-VaD may be through inhibiting the NLRP3 inflammasome, TNF signaling pathway, and toll-like receptor signaling pathways. Subsequently, key compounds were docked with related proteins in the NLRP3 inflammasome (NLRP3, ASC, caspase-1, interleukin-18, and interleukin-1 β) using molecular docking technology. The compounds were found to spontaneously bind to the proteins.

CONCLUSIONS

YZTM may exert an anti-VaD effect through inhibition of the NLRP3 inflammasome. In addition, TNF signaling pathway and toll-like receptor signaling pathway may also be its underlying mechanism. The application of network pharmacology and molecular docking technology may provide a novel method for research of Chinese herbal medicine. YZTM may also provide a complementary treatment option for patients with VaD.

The Relevance of SNPs at 3'UTR Region of CASP7 and miR-371b-5p Associated Diseases: A Computational Analysis

The process of genetically programmed cell death, or apoptosis, plays a crucialrolein cellular homeostasis and gene expression. Disruption of apoptosis may lead to aberrant immune responses, cancer, and neurodegenerative diseases. Single nucleotide polymorphisms (SNPs) present in various microRNA (miRNA) genes and targets being an alteration of miRNA activity resulting in human diseases. Evidence reported that SNPs increase/decrease the effectiveness of the interaction between miRNAs and their target genes associated with diseases. The primary purpose of this study is not only to identify miRSNPs on the CASP7 gene (caspase-7) and SNPs in miRNA genes targeting 3'UTR but also to evaluate the effect of thesegene variations in apoptosis and their associated diseases. We detected 120 miRNAs binding sites and 27 different SNPs in binding sites of miRNA in 3'UTR of the CASP7 gene by ten different online softwares. Interestingly, miR-371b-5p's binding site on CASP7 has an SNP (rs576198588, G/T) on CASP7 3'UTR, and its genomic sequence has an SNP (rs751339395, G/T) at the same nucleotide with rs576198588. Similarly, two other SNPs (rs774879764, C/G rs750389063, C/T) were identified at the first position binding site of miR-371b-5p. Here, miRSNP (rs576198588) at CASP7 3'UTR and SNP (rs751339395) at miR-371b-5p genomic sequence cross-matches at the same site of binding region. Besides, miR-371b-5p targets many apoptosis-related genes (HIP1, TRIAP1, GSKIP, NIN, DAP, CAAP1, XIAP, TMBIM1, TMBIM4, TNFRSF10A, RAD21, AKT1, BAG1, BAG4) even though it had no apoptosis correlated interaction demonstrated formerly. It assures that CASP7 could have a significant consequence on apoptosis through different pathways. Henceforth, this study was representing and signifying an influential connotation among miR-371b-5p and apoptosis via computational exploration and recommended to have better insight.

Motor Cortex and Hippocampus Display Decreased Heme Oxygenase Activity 2 Weeks After Ventricular Fibrillation Cardiac Arrest in Rats

Heme oxygenase (HO) and biliverdin reductase (BVR) activities are important for neuronal function and redox homeostasis. Resuscitation from cardiac arrest (CA) frequently results in neuronal injury and delayed neurodegeneration that typically affect vulnerable brain regions, primarily hippocampus (Hc) and motor cortex (mC), but occasionally also striatum and cerebellum. We questioned whether these delayed effects are associated with changes of the HO/BVR system. We therefore analyzed the activities of HO and BVR in the brain regions Hc, mC, striatum and cerebellum of rats subjected to ventricular fibrillation CA (6 min or 8 min) after 2 weeks following resuscitation, or sham operation. From all investigated regions, only Hc and mC showed significantly decreased HO activities, while BVR activity was not affected. In order to find an explanation for the changed HO activity, we analyzed protein abundance and mRNA expression levels of HO-1, the inducible, and HO-2, the constitutively expressed isoform, in the affected regions. In both regions we found a tendency for a decreased immunoreactivity of HO-2 using immunoblots and immunohistochemistry. Additionally, we investigated the histological appearance and the expression of markers indicative for activation of microglia [tumor necrosis factor receptor type I (TNFR1) mRNA and immunoreactivity for ionized calcium-binding adapter molecule 1 (Iba1])], and activation of astrocytes [immunoreactivity for glial fibrillary acidic protein (GFAP)] in Hc and mC. Morphological changes were detected only in Hc displaying loss of neurons in the cornu ammonis 1 (CA1) region, which was most pronounced in the 8 min CA group. In this region also markers indicating inflammation and activation of pro-death pathways (expression of HO-1 and TNFR1 mRNA, as well as Iba1 and GFAP immunoreactivity) were upregulated. Since HO products are relevant for maintaining neuronal function, our data suggest that neurodegenerative processes following CA may be associated with a decreased capacity to convert heme into HO products in particularly vulnerable brain regions.

Cerebrovascular inflammation: A critical trigger for neurovascular injury?

The cerebrovascular system is not only inert bystandard that support the metabolic demands of the brain but also elicit the barrier functions against risk factors mediated neurovascular injury. The onsets of cerebrovascular inflammation are considered as stimuli that can provoke the host defense system and trigger the development of neurological disorders. Homeostasis of the brain function is regulated by the movement of endothelial, glial, and neuronal cells within the neurovascular unit (NVU), which acts as a "platform" for the coordinated action of anti- and pro-inflammatory mechanisms. The cerebrovascular system plays an integral role in the inflammatory response by either producing or expressing a variety of cytokines, adhesion molecules, metalloproteinases, and serine proteases. Excessive inflammatory cytokine production can further be affecting the blood-brain barrier (BBB) integrity and lead to brain tissue damage. In this review, we summarize the more recent evidence highlighting the importance of cerebrovascular injury in terms of risk prediction, and the mechanisms mediating the upregulation of inflammatory mediators in cerebrovascular dysfunction and neurodegeneration.

Dexmedetomidine pretreatment inhibits cerebral ischemia/reperfusion‑induced neuroinflammation via activation of AMPK

Focal ischemia/reperfusion (I/R) injury induced cerebral inflammation, aggravates brain damage. The aim of the present study was to investigate the protective mechanisms of dexmedetomidine (DEX) on I/R brain injury in rats. Sprague‑Dawley rats were divided to seven experimental groups (18 rats/group): Sham surgery; middle cerebral artery occlusion (MCAO) surgery (90 min); DEX10 [10 µg/kg intraperitoneal (i.p.) injection 30 min prior to MCAO]; DEX50 (50 µg/kg i.p. 30 min prior to MCAO); DEX100 (100 µg/kg i.p. 30 min prior to MCAO); DEX50+Yohimbine [YOH; 5 mg/kg 10 min prior to DEX (50 µg/kg i.p.) administration and MCAO] and YOH (5 mg/kg 40 min prior to MCAO). At 24 h post‑MCAO surgery, neurological deficit was examined by staining damaged brain tissues with 2,3,5‑triphenyltetrazolium chloride. Neuronal apoptosis in the cerebral cortex was histologically assessed by terminal deoxynucleotidyl‑transferase‑mediated dUTP nick end labeling staining, and the expression levels of phosphorylated (p)‑AMP‑activated protein kinase (AMPK; Thr172) was detected by western blotting. In addition, the expression levels of tumor necrosis factor (TNF)‑α and interleukin (IL)‑1β were assessed by ELISA. At days 1, 2 and 5 following I/R, motor functions were assessed by an observer blinded to the study. The brain infarct size, neurological deficit scores, number of apoptotic neurons, expression levels of pro‑inflammatory cytokines TNF‑α and IL‑1β were increased following MCAO, whereas the motor function scores were reduced. Pretreatment with DEX prior to MCAO can reverse the effects induced by I/R. Compared with rats in the Sham group, the expression levels of p‑AMPK were mildly increased in the MCAO group and highly increased in the three DEX‑treatment groups. Pretreatment with YOH reversed the above effects of DEX and produced a similar level of cerebral I/R injury. The results demonstrated that precondition with DEX exhibited anti‑inflammatory effects on brain ischemic injury mediated by AMPK signal pathway.

Heme oxygenase-1 deficiency promotes severity of sepsis in a non-surgical preterm mouse model

BACKGROUND

Sepsis in preterm infants is associated with systemic inflammatory responses. The stress-response protein heme oxygenase-1 (HO-1) has protective anti-inflammatory properties. Recently, we reported a protective role of HO-1 using our non-surgical cecal slurry (CS) model in wild-type (WT) mouse pups. Here, we extend these findings to investigate the association of HO-1 deficiency with sepsis severity.

METHODS

Adapting the Wynn model, we induced sepsis in 4-day-old HO-1-deficient (HO-1^+/-, Het) pups to determine if HO-1 deficiency affected survival rates at the LD40 (2.0 mg/g) of WT pups. To see if HO-1 induction affected sepsis severity, we gave 30-μmol heme/kg subcutaneously to 3-day-old mice 24 h prior to sepsis induction.

RESULTS

Post-sepsis induction, Het pups had a mortality of 85.0% (n = 20) and increased expression of the pro-inflammatory gene in the livers and affected hematologic profiles. Heme treatment 24 h prior to sepsis induction significantly increased liver HO activity, reduced mortality to 24.5% (n = 17), attenuated inflammatory responses, reduced spleen bacterial counts, and significantly increased peripheral neutrophils.

CONCLUSIONS

A partial deficiency in HO-1 increased the progression and mortality in sepsis. Furthermore, induction of HO-1 significantly reduced the mortality even in Het pups. Thus, we conclude that HO-1 plays an important role in the protection against preterm sepsis.