Regional variations in allergen-induced airway inflammation correspond to changes in soluble guanylyl cyclase heme and expression of heme oxygenase-1.

Asthma is characterized by airway remodeling and hyperreactivity. Our earlier studies determined that the nitric oxide (NO)-soluble guanylyl cyclase (sGC)-cGMP pathway plays a significant role in human lung bronchodilation. However, this bronchodilation is dysfunctional in asthma due to high NO levels, which cause sGC to become heme-free and desensitized to its natural activator, NO. In order to determine how asthma impacts the various lung segments/lobes, we mapped the inflammatory regions of lungs to determine whether such regions coincided with molecular signatures of sGC dysfunction. We demonstrate using murine models of asthma (OVA and CFA/HDM) that the inflamed segments of these murine lungs can be tracked by upregulated expression of HO1 and these regions in turn overlap with regions of heme-free sGC as evidenced by a decreased sGC-α1ß1 heterodimer and an increased response to heme-independent sGC activator, BAY 60-2770, relative to naïve uninflamed regions. We also find that NO generated from iNOS upregulation in the inflamed segments has a higher impact on developing heme-free sGC as increasing iNOS activity correlates linearly with elevated heme-independent sGC activation. This excess NO works by affecting the epithelial lung hemoglobin (Hb) to become heme-free in asthma, thereby causing the Hb to lose its NO scavenging function and exposing the underlying smooth muscle sGC to excess NO, which in turn becomes heme-free. Recognition of these specific lung segments enhances our understanding of the inflamed lungs in asthma with the ultimate aim to evaluate potential therapies and suggest that regional and not global inflammation impacts lung function in asthma.

GAPDH is involved in the heme-maturation of myoglobin and hemoglobin.

GAPDH, a heme chaperone, has been previously implicated in the incorporation of heme into iNOS and soluble guanylyl cyclase (sGC). Since sGC is critical for myoglobin (Mb) heme-maturation, we investigated the role of GAPDH in the maturation of this globin, as well as hemoglobins α, ß, and γ. Utilizing cell culture systems, we found that overexpression of wild-type GAPDH increased, whereas GAPDH mutants H53A and K227A decreased, the heme content of Mb and Hbα and Hbß. Overexpression of wild-type GAPDH fully recovered the heme-maturation inhibition observed with the GAPDH mutants. Partial rescue was observed by overexpression of sGCß1 but not by overexpression of a sGCΔß1 deletion mutant, which is unable to bind the sGCα1 subunit required to form the active sGCα1ß1 complex. Wild type and mutant GAPDH was found to be associated in a complex with each of the globins and Hsp90. GAPDH at endogenous levels was found to be associated with Mb in differentiating C2C12 myoblasts, and with Hbγ or Hbα in differentiating HiDEP-1 erythroid progenitor cells. Knockdown of GAPDH in C2C12 cells suppressed Mb heme-maturation. GAPDH knockdown in K562 erythroleukemia cells suppressed Hbα and Hbγ heme-maturation as well as Hb dimerization. Globin heme incorporation was not only dependent on elevated sGCα1ß1 heterodimer formation, but also influenced by iron provision and magnitude of expression of GAPDH, d-aminolevulinic acid, and FLVCR1b. Together, our data support an important role for GAPDH in the maturation of myoglobin and γ, ß, and α hemoglobins.

Ligand decorated biodegradable nanomedicine in the treatment of cancer.

Cancer is one of the major global health problems, responsible for the second-highest number of deaths. The genetic and epigenetic changes in the oncogenes or tumor suppressor genes alter the regulatory pathways leading to its onset and progression. Conventional methods are used in appropriate combinations for the treatment. Surgery effectively treats localized tumors; however, it fails to treat metastatic tumors, leading to a spread in other organs, causing a high recurrence rate and death. Among the different strategies, the nanocarriers-based approach is highly sought for, but its nonspecific delivery can cause a profound side effect on healthy cells. Targeted nanomedicine has the advantage of targeting cancer cells specifically by interacting with the receptors overexpressed on their surface, overcoming its non-specificity to target healthy cells. Nanocarriers prepared from biodegradable and biocompatible materials are decorated with different ligands by encapsulating therapeutic or diagnostic agents or both to target cancer cells overexpressing the receptors. Scientists are now utilizing a theranostic approach to simultaneously evaluate nanocarrier bio-distribution and its effect on the treatment regime. Herein, we have summarized the recent 5-year efforts in the development of the ligands decorated biodegradable nanocarriers, as a targeted nanomedicine approach, which has been highly promising in the treatment of cancer.

Clinical Importance of Estrogen Receptor 1 (ESR1) Gene Polymorphisms and Their Expression Patterns in Coronary Artery Disease Patients: A Study from India.

The influence of Estrogen Receptor 1 (ESR1) gene -397T>C (PvuII) and -351A>G (XbaI) polymorphisms on the risk of development of coronary artery disease (CAD) in the north Indian population was analysed. We hypothesized that ESR1 gene polymorphisms may influence the susceptibility to CAD through variation in Estrogen Receptor α (ERα) expression. To assess this concept, we evaluated ERα mRNA expression in blood plasma of CAD patients. The study included hundred CAD patients who showed presence of greater than 50% luminal stenosis in at least one major coronary artery in angiography along with hundred age and sex matched healthy controls. The ESR1 polymorphisms were investigated by PCR-RFLP. Quantitative Real Time PCR was carried out for the measurement of ERα mRNA expression. The results showed that genotypic frequencies of ESR1 -397T>C and -351A>G gene polymorphisms were significantly higher in CAD patients than control subjects (p < 0.0001). A significantly increased CAD risk was also found in dominant and codominant inheritance model for both of the SNPs. In gender based analysis these findings were replicated only in male subgroup. In case of -397T>C polymorphism, the ERα mRNA expression was highest in CAD patients with wild type homozygous TT genotype (2-∆ct = 0.28). A mutant 'C' allele, dose dependent, significant decrease in trend in ERα mRNA expression was observed, with lowest expression in mutant homozygous CC genotype (2-∆ct = 0.09), and intermediate expression level in heterozygous TC genotype (2-∆ct = 0.14) subgroups of CAD patients. In conclusion, this study demonstrates a significantly heightened risk of CAD associated with the inheritance of mutant genotypes of ESR1 -397T>C and -351A>G gene polymorphisms, in the north Indian population. This is the first report of a lowered ERα mRNA expression in conjunction with the presence of mutant 'C' allele of ESR1 -397T>C polymorphism with consequent increased CAD susceptibility.

Hemoglobin resident in the lung epithelium is protective for smooth muscle soluble guanylate cyclase function.

Hemoglobin (Hb) present in the lung epithelium is of unknown significance. However Hb being an nitric oxide (NO) scavenger can bind to NO and reduce its deleterious effects. Hence we postulated an NO scavenging role for this lung Hb. Doing transwell co-culture with bronchial epithelial cells, A549/16-HBE (apical) and human airway smooth muscle cells (HASMCs as basal), we found that Hb can protect the smooth muscle soluble guanylyl cyclase (sGC) from excess NO. Inducing the apical A549/16-HBE cells with cytokines to trigger iNOS expression and NO generation caused a time dependent increase in SNO-sGC and this was accompanied with a concomitant drop in sGC-α1ß1 heterodimerization. Silencing Hbαß in the apical cells further increased the SNO on sGC with a faster drop in the sGC heterodimer and these effects were additive along with further silencing of thioredoxin 1 (Trx1). Since heme of Hb is critical for NO scavenging we determined the Hb heme in a mouse model of allergic asthma (OVA) and found that Hb in the inflammed OVA lungs was low in heme or heme-free relative to those of naïve lungs. Further we established a direct correlation between the status of the sGC heterodimer and the Hb heme from lung samples of human asthma, iPAH, COPD and cystic fibrosis. These findings present a new mechanism of protection of lung sGC by the epithelial Hb, and suggests that this protection maybe lost in asthma or COPD where lung Hb is unable to scavenge the NO due to it being heme-deprived.

Hsp90 in Human Diseases: Molecular Mechanisms to Therapeutic Approaches.

The maturation of hemeprotein dictates that they incorporate heme and become active, but knowledge of this essential cellular process remains incomplete. Studies on chaperon Hsp90 has revealed that it drives functional heme maturation of inducible nitric oxide synthase (iNOS), soluble guanylate cyclase (sGC) hemoglobin (Hb) and myoglobin (Mb) along with other proteins including GAPDH, while globin heme maturations also need an active sGC. In all these cases, Hsp90 interacts with the heme-free or apo-protein and then drives the heme maturation by an ATP dependent process before dissociating from the heme-replete proteins, suggesting that it is a key player in such heme-insertion processes. As the studies on globin maturation also need an active sGC, it connects the globin maturation to the NO-sGC (Nitric oxide-sGC) signal pathway, thereby constituting a novel NO-sGC-Globin axis. Since many aggressive cancer cells make Hbß/Mb to survive, the dependence of the globin maturation of cancer cells places the NO-sGC signal pathway in a new light for therapeutic intervention. Given the ATPase function of Hsp90 in heme-maturation of client hemeproteins, Hsp90 inhibitors often cause serious side effects and this can encourage the alternate use of sGC activators/stimulators in combination with specific Hsp90 inhibitors for better therapeutic intervention.

Nitric Oxide Trickle Drives Heme into Hemoglobin and Muscle Myoglobin.

Ever since the days of NO being proclaimed as the "molecule of the year", the molecular effects of this miracle gas on the globins have remained elusive. While its vasodilatory role in the cardiopulmonary system and the vasculature is well recognized, the molecular underpinnings of the NO-globin axis are incompletely understood. We show, by transwell co-culture of nitric oxide (NO) generating, HEK eNOS/nNOS cells, and K562 erythroid or C2C12 muscle myoblasts, that low doses of NO can effectively insert heme into hemoglobin (Hb) and myoglobin (Mb), making NO not only a vasodilator, but also a globin heme trigger. We found this process to be dependent on the NO flux, occurring at low NO doses and fading at higher doses. This NO-triggered heme insertion occurred into Hb in just 30 min in K562 cells and into muscle Mb in C2C12 myoblasts between 30 min and 1 h, suggesting that the classical effect of NO on upregulation of globin (Hb or Mb) is just not transcriptional, but may involve sufficient translational events where NO can cause heme-downloading into the apo-globins (Hb/Mb). This effect of NO is unexpected and highlights its significance in maintaining globins in its heme-containing holo-form, where such heme insertions might be required in the circulating blood or in the muscle cells to perform spontaneous functions.

Low levels of nitric oxide promotes heme maturation into several hemeproteins and is also therapeutic.

Nitric oxide (NO) is a signal molecule and plays a critical role in the regulation of vascular tone, displays anti-platelet and anti-inflammatory properties. While our earlier and current studies found that low NO doses trigger a rapid heme insertion into immature heme-free soluble guanylyl cyclase ß subunit (apo-sGCß), resulting in a mature sGC-αß heterodimer, more recent evidence suggests that low NO doses can also trigger heme-maturation of hemoglobin and myoglobin. This low NO phenomena was not only limited to sGC and the globins, but was also found to occur in all three nitric oxide synthases (iNOS, nNOS and eNOS) and Myeloperoxidase (MPO). Interestingly high NO doses were inhibitory to heme-insertion for these hemeproteins, suggesting that NO has a dose-dependent dual effect as it can act both ways to induce or inhibit heme-maturation of key hemeproteins. While low NO stimulated heme-insertion of globins required the presence of the NO-sGC-cGMP signal pathway, iNOS heme-maturation also required the presence of an active sGC. These effects of low NO were significantly diminished in the tissues of double (n/eNOS-/-) and triple (n/i/eNOS-/-) NOS knock out mice where lung sGC was found be heme-free and the myoglobin or hemoglobin from the heart/lungs were found be low in heme, suggesting that loss of endogenous NO globally impacts the whole animal and that this impact of low NO is both essential and physiologically relevant for hemeprotein maturation. Effects of low NO were also found to be protective against ischemia reperfusion injury on an ex vivo lung perfusion (EVLP) system prior to lung transplant, which further suggests that low NO levels are also therapeutic.

S1P signaling, its interactions and cross-talks with other partners and therapeutic importance in colorectal cancer.

Sphingosine-1-Phosphate (S1P) plays an important role in normal physiology, inflammation, initiation and progression of cancer. Deregulation of S1P signaling causes aberrant proliferation, affects survival, leads to angiogenesis and metastasis. Sphingolipid rheostat is crucial for cellular homeostasis. Discrepancy in sphingolipid metabolism is linked to cancer and drug insensitivity. Owing to these diverse functions and being a potent mediator of tumor growth, S1P signaling might be a suitable candidate for anti-tumor therapy or combination therapy. In this review, with a focus on colorectal cancer we have summarized the interacting partners of S1P signaling pathway, its therapeutic approaches along with the contribution of S1P signaling to various cancer hallmarks.

Molecular Evaluation of Exon 8 Cystathionine rs5742905T T>C Gene Polymorphism and Determination of its Frequency, Distribution Pattern, and Association with Susceptibility to Coronary Artery Disease in the North Indian Population.

BACKGROUND: The protein coded by the cystathionine ß synthase (CBS) gene acts as a catalyzer and converts homocysteine to cystathionine. Impairment of the CBS gene leads to homocystinuria by cystathionine ß synthase deficiency which is linked to Coronary Artery Disease. A number of polymorphisms studies have been performed on the cystathionine ß synthase gene. In the current study, we planned to analyze the influence of CBS T833C gene polymorphism(exon 8 cystathionine rs5742905T T>C), its association with Coronary Artery Disease development, and its progression in the north Indian population. MATERIALS AND METHODS: The present study comprises 100 angiographically confirmed CAD patients and 100 age and sex-matched healthy controls. A total of 50% or more luminal stenosis at one major coronary artery was considered for the inclusion criteria of the cases. The investigation of T833C polymorphism in the CBS gene was performed by PCR- RFLP technique. RESULTS: As a result, we found that homozygous mutant (CC) and heterozygous (TC) genotypes of CBS T833C gene polymorphism were significantly higher in CAD patients than in healthy subjects. We also observed a substantially increased CAD risk in dominant, codominant inheritance, and allele-specific models for the CBS T833C gene polymorphism. We analyzed the differential distribution with respect to disease severity, but there was no significant association (p=0.96). CONCLUSION: In conclusion, this study demonstrates that CBS T833C gene polymorphism plays a key role in developing coronary artery disease and its progression.

Elucidation of Epigenetic Landscape in Coronary Artery Disease: A Review on Basic Concept to Personalized Medicine.

Despite extensive clinical research and management protocols applied in the field of coronary artery diseases (CAD), it still holds the number 1 position in mortality worldwide. This indicates that we need to work on precision medicine to discover the diagnostic, therapeutic, and prognostic targets to improve the outcome of CAD. In precision medicine, epigenetic changes play a vital role in disease onset and progression. Epigenetics is the study of heritable changes that do not affect the alterations of DNA sequence in the genome. It comprises various covalent modifications that occur in DNA or histone proteins affecting the spatial arrangement of the DNA and histones. These multiple modifications include DNA/histone methylation, acetylation, phosphorylation, and SUMOylation. Besides these covalent modifications, non-coding RNAs-viz. miRNA, lncRNA, and circRNA are also involved in epigenetics. Smoking, alcohol, diet, environmental pollutants, obesity, and lifestyle are some of the prime factors affecting epigenetic alterations. Novel molecular techniques such as next-generation sequencing, chromatin immunoprecipitation, and mass spectrometry have been developed to identify important cross points in the epigenetic web in relation to various diseases. The studies regarding exploration of epigenetics, have led researchers to identify multiple diagnostic markers and therapeutic targets that are being used in different disease diagnosis and management. Here in this review, we will discuss various ground-breaking contributions of past and recent studies in the epigenetic field in concert with coronary artery diseases. Future prospects of epigenetics and its implication in CAD personalized medicine will also be discussed in brief.

Correction to: Ectopic PD-L1 expression in JAK2 (V617F) myeloproliferative neoplasm patients is mediated via increased activation of STAT3 and STAT5.

In the original publication, third author name was incorrectly published as "Ab Rashid Mir". The correct name should read as "Rashid Mir".

Ectopic PD-L1 expression in JAK2 (V617F) myeloproliferative neoplasm patients is mediated via increased activation of STAT3 and STAT5.

Escalated PD-L1 expression has been identified during malignant transformation in a number of cancer types and helps cancer cells escape an effective anti-tumor immune response. The mechanisms underlying escalated production of PD-L1 in many cancers, however, are still far from clear. We studied PD-L1, STAT3 and STAT5 mRNA expression using qRT-PCR in 72 BCR/ABL1 negative myeloproliferative neoplasm (MPN) patients (39 polycythemia vera and 33 essential thrombocythemia). Furthermore, phosphorylation status of STAT3 and STAT5 was studied using immunoblotting in the same patients. All MPN patients were first screened for JAK2 (V617F) mutation by tetra-primer ARMS-PCR, followed by quantification of JAK2 (V617F) mutation burden in all V617F positive MPN patients by ASO-PCR. Patients were screened for BCR/ABL1 fusion gene transcripts to rule out Ph positive status. Our findings showed that mRNA levels of PD-L1 and STAT3 were significantly higher in JAK2 (V617F) MPN patients, while as STAT5 was insignificantly upregulated. STAT3 and STAT5 phosphorylation was seen to be higher in JAK2 (V617F) MPN patients compared to the JAK2 (WT) patients. Upregulation of PD-L1, STAT3 and STAT5 was significantly associated with JAK2 (V617F) percentage in MPN patients. PD-L1, STAT3 and STAT5 expression significantly and positively correlated with JAK2 (V617F) allele burden. In addition, significant coexpression of PD-L1 with STAT3 and STAT5 was observed in MPN patients. In summary, JAK2 (V617F) mutation is accompanied by increased PD-L1 expression and this PD-L1 over expression is mediated by JAK2 (V617F) mainly through STAT3, while as STAT5 may play a minor role.