Since the start of the novel coronavirus SARS-Cov-2 pandemic, a disease that has become one of the world’s greatest global health challenges, the role of the immune system has been at the forefront of scientific studies. The pathophysiology of COVID-19 is complex, which is evident by those at higher risk for poor outcome. Multiple systems contribute to thrombosis and inflammation seen in COVID-19 patients, including neutrophil dysfunction, platelet activation, endothelial cell activation. Understanding how the immune system functions in different patient cohorts (particularly given recent emerging events with the Oxford/AstraZeneca vaccine) is vital to understanding the pathophysiology of this devastating disease and for subsequent development of novel therapeutic targets and expedite possible drug repurposing strategies that could benefit society on a global scale.
Sepsis causes multi-organ dysfunction and is a major cause of death in intensive care units, but there are no treatments that reverse the pathophysiological effects of sepsis. Vitamin C has antioxidant, anti-inflammatory, anticoagulant and immune modulatory actions, so is a potential treatment for sepsis. Recent clinical trials of high-doses of intravenous vitamin C (6-16 g/day) had variable effects. Since much higher doses are without side-effects in cancer and burns patients, we studied the effects of a mega-dose of intravenous sodium ascorbate (150 g/40 kg) in a clinically relevant ovine model of sepsis. This treatment dramatically improved the clinical state and over 3-7-h improved cardiovascular, pulmonary, hepatic and renal function and reduced body temperature. In a critically ill COVID-19 patient, intravenous sodium ascorbate (60 g) restored arterial pressure, improved renal function and increased arterial blood oxygen levels. Clinical trials are testing the effectiveness of mega-dose vitamin C in septic patients.
Emerging data shows pregnant women with COVID-19 are at significantly higher risk of severe outcomes compared to non-pregnant women of similar age. This review discusses the invaluable insight revealed from vaccine clinical trials in women who were vaccinated and inadvertently became pregnant during the trial period. It further explores a number of clinical avenues in their management and proposes a drug development strategy in-line with clinical trials for vaccines and drug treatments for the drug development community. Little is known of the long-term effects of COVID-19 on the mother and the baby. We provide a rationale for our hypothesis that COVID-19 predisposes pregnant women to cardiovascular diseases later in life, in a similar way, to preeclampsia and may increase the risk of preeclampsia in their subsequent pregnancy. This is an ever-evolving landscape and early knowledge for healthcare providers and drug innovators is offered to ensure benefits outweigh the risks.
Background and Purpose: Many pain-triggering nociceptor neurons express TRPV1 or TRPA1, cation-selective channels with large pores that enable permeation of QX-314, a cationic analogue of lidocaine. Co-application of QX-314 with TRPV1 or TRPA1 activators can silence nociceptors. We now describe BW-031, a novel more potent cationic sodium channel inhibitor, test whether its application alone can inhibit the pain associated with tissue inflammation, and whether this strategy can also inhibit cough. Experimental Approach: We characterized BW-031 inhibition of sodium channels and tested BW-031 in three models of inflammatory pain: rat paw inflammation produced by Complete Freund’s Adjuvant injection or surgical incision and a mouse paw UV burn model. We also tested the ability of BW-031 to inhibit cough induced by inhalation of dilute citric acid in guinea pigs. Key Results: BW-031 inhibited Nav1.7 and Nav1.1 channels with ~6-fold greater potency than QX-314 when introduced inside cells and entered capsaicin-activated TRPV1 expressing sensory neurons. BW-031 inhibited inflammatory pain in all three models, producing more effective and longer-lasting inhibition of pain than QX-314 in the mouse UV burn model. BW-031 was also effective in reducing cough counts by 78-90% when applied intratracheally under isoflurane anesthesia or by aerosol inhalation in awake guinea pigs with airway inflammation produced by ovalbumin sensitization. Conclusion and Implications: BW-031 a novel cationic sodium channel inhibitor can be applied locally as a single agent to inhibit inflammatory pain and also effectively inhibits cough in a guinea pig model of nociceptor-activated cough, suggesting a new clinical approach to treating cough.
Background and Purpose. Pseudomonas aeruginosa is a main cause of ventilator-associated pneumonia (VAP) with drug-resistant bacteria. Bacteriophage therapy has experienced resurgence to compensate for the limited development of novel antibiotics. However, phage therapy is limited to a compassionate use so far, resulting from lack of adequate studies in relevant pharmacological models. We used a pig model of VAP caused by P. aeruginosa that recapitulates essential features of human disease to study the antimicrobial efficacy of nebulized-phage therapy. Experimental Approach. (i) Lysis kinetic assays were performed to evaluate in vitro phage antibacterial efficacy against P. aeruginosa and select relevant combinations of lytic phages. (ii) The efficacy of the phage combinations was investigated in vivo (murine model of P. aeruginosa lung infection). (iii) We determined the optimal conditions to ensure efficient phage delivery by aerosol during mechanical ventilation. (iv) Lung antimicrobial efficacy of inhaled-phage therapy was evaluated in pigs, which were anesthetized, mechanically ventilated and infected with P. aeruginosa. Key Results. By selecting an active phage cocktail and optimizing aerosol delivery conditions, we were able to deliver high phage concentrations in the lungs, which resulted in a rapid and marked reduction in P. aeruginosa density (1.5 Log reduction, p<0.001). No phage was detected in the sera and urines throughout the experiment. Conclusion and Implications. Our findings demonstrated: (i) the feasibility of delivering large amounts of active phages by nebulization during mechanical ventilation, (ii) rapid control of in situ infection by inhaled bacteriophage in an experimental model of VAP with high translational value.
COVID-19 is a complex disease and many difficulties are faced today especially in the proper choice of pharmacological treatments. The role of antiviral agents for COVID-19 is still being investigated. The evidence for immunomodulatory and anti-inflammatory drugs is quite conflicting, while the use of corticosteroids is supported by robust evidence. The use of heparins in hospitalized critically ill patients is preferred over other anticoagulants. Lastly, conflicting data were found regarding to the use of convalescent plasma and vitamin D. According to data shared by the WHO, many vaccines are under phase 3 clinical trials and some of them already received the marketing approval in EU countries and in the US. In conclusion, drugs repurposing has represented the main approach recently used in the treatment of patients with COVID-19. At this moment, the analysis of efficacy and safety data of drugs and vaccines used in real life context is strongly needed.
Background and Purpose: The development of effective therapeutic strategies against Alzheimer’s disease (AD) remains a challenge. I2 Imidazoline receptors (I2-IR) ligands have a neuroprotective role in AD. While co-treatment of acetylcholinesterase inhibitors with neuroprotective agents have shown better effects on the prevention of dementia. Here, we assessed the potential therapeutic effect of the I2-IR ligand LSL60101, donepezil and their combination in 5XFAD mice. Experimental Approach: 5XFAD female mice were treated with low doses of LSL60101 (1mg/kg/day), donepezil (1mg/kg/day), and donepezil plus LSL60101 (1+1mg/kg/day), during 4 weeks per os. Novel object recognition, Morris water maze, open field, elevated plus maze and three-chamber tests were employed to evaluate the cognitive and behavioural status of the mice after treatment. The effects of the treatments on AD-like pathology were assessed with immunohistochemistry, Western blot and qPCR. Key results: Chronic low-dose treatment with LSL60101 and donepezil reversed cognitive deficits and impaired social behaviour. LSL60101 treatment did not affect anxiety-like behaviour in contrast to donepezil. In the 5XFAD brains, LSL60101 and donepezil/LSL60101 treatments decreased Aβ-pathology and Tau hyperphosphorylation, and these alterations were accompanied by decreased microglia marker Iba-1 levels and increased Trem2 gene expression. LSL60601 and donepezil decreased glial fibrillary acidic protein (GFAP) astrocytic marker reactivity. However, only LSL60601 treatment significantly increased the levels of the synaptic markers post-density 95 (PSD95) and synaptophysin (SYN). Conclusion and implications: Our results suggest that chronic low dose treatment with selective I2-IR ligands can be an effective treatment for AD and provide insights into combination treatments of symptomatic and disease-modifying drugs
Na+,K+ATPase (NKA), a transmembrane protein essential for maintaining the electrochemical gradient across the plasma membrane, acts as a receptor for cardiotonic steroids (CTS) such as ouabain. CTS binding to NKA, triggers signalling pathways or inhibits NKA activity in a concentration-dependent manner, resulting in a modulation of Ca2+ levels, which are essential for homeostasis in neurons. However, most of the pharmacological strategies for avoiding neuronal death do not target NKA activity, due to its complexity and poor comprehension of the mechanisms involved in NKA modulation. The present review aims to discuss two points regarding the interplay between NKA and Ca2+ signalling in the brain: NKA impairment causing illness as well as neuronal death due to Ca2+ signalling and benefits to the brain by modulating NKA activity. These interactions play an essential role in neuronal cell fate determination and are relevant to finding new targets for the treatment of neurodegenerative diseases.
Background and Purpose: Liver fibrosis is one of the leading causes of morbidity and mortality worldwide of which no acceptable therapy exists. Accumulating evidence supports that glioma-associated oncogene homologue 1(GLI1) is a potentially important therapeutic target for liver fibrosis. This study investigates the antifibrotic activities and potential mechanisms of Physalin B (PB), a natural Solanaceae compound. Experimental Approach: Mice subjected to CCl4 challenge and bile duct ligation were used to study the antifibrotic effects of PB in vivo. Mouse primary hepatic stellate cells (pHSCs) and human HSC line LX‐2 also served as an in vitro liver fibrosis model. Liver fibrogenic genes, GLI1 downstream genes were examined using western blot and real-time PCR analyses. GLI1 acetylation and LAP2α-HDAC1 interaction were analyzed by coimmunoprecipitation. Key Results: In animal models, PB administration attenuated hepatic histopathological injury, collagen accumulation, and reduced the expression of fibrogenic genes. PB dose‐dependently suppressed fibrotic marker expression in LX‐2 cells and mouse pHSCs. Mechanistic studies showed PB inhibited GLI activity in a non-canonical Hedgehog signaling. PB blocked lamina-associated polypeptide 2 α (LAP2α)/ histone deacetylase 1 (HDAC1) complex formation thereby inhibited HDAC1mediated GLI1 deacetylation. PB downregulated the acetylation and expression of GLI1, and subsequently inhibiting HSC activation. Conclusions and Implications: PB exerted potent antifibrotic effects in vitro and in vivo by disrupting the LAP2α/HDAC1 complex, increasing GLI1 acetylation and inactivating GLI1. This indicates that PB may be a potential therapeutic candidate for the treatment of liver fibrosis.
Diabetes is a chronic metabolic disorder associated with the accelerated development of macrovascular (atherosclerosis, coronary artery disease) and microvascular complications (nephropathy, retinopathy and neuropathy), which remain the principal cause of mortality and morbidity in this population. Current understanding of cellular and molecular pathways of diabetes-driven vascular complications as well as therapeutic interventions have arisen from studying disease pathogenesis in animal models. Diabetes-associated vascular complications are multi-faceted, involving the interaction between various cellular and molecular pathways. Thus, the choice of an appropriate animal model to study vascular pathogenesis is important in our quest to identify innovative and mechanism-based targeted therapies to reduce the burden of diabetic complications. Herein, we provide up-to-date information on available mouse models of both Type 1 and Type 2 diabetic vascular complications as well as experimental analysis and research outputs.
Epitranscriptomics is an exciting emerging area that studies biochemical modifications of RNA. The field is boosted by the technical efforts of the last decade to characterize and quantify RNA modifications which have led to a map of post-transcripcional RNA marks in normal cell fate and develoment. However, the scientific interest has been fueled by the discovery of aberrant epitranscriptomes associated with human diseases, mainly cancer. The challenge is now to see whether epitrancriptomics offers a tunable mechanims to be targeted by small- molecule intervention. In this review, we will describe the principal RNA modifications (with a focus on mRNA), summarize the latest scientific evidences of their dysregulation in cancer and provide an overview of the state-of-the-art drug discovery to target the epitranscriptome. Finally, we will discuss the principal challenges in the field of chemical biology and drug development to increase the potential of targeted-RNA for clinical benefit.
IImmunodeficiency and hyperinflammation characterize COVID-19 associated states; thus, repurposing of multiple cytokine and/or anti-cytokine drugs currently being used in other therapeutic areas has been suggested as a potential therapeutic strategy in COVID-19 patients. Clinical trials involving these drugs target the most frequent and life-threatening peripheral consequences of the disease, mainly focusing on lung, heart, and coagulation functions; however, a growing number of reports describe a wide range of COVID-associated neurological manifestations (altogether defined as neuro-COVID) including anosmia, seizures, confusion, stroke, encephalopathy, and paralysis. Notably, the underlying pathophysiological mechanisms for neuro-COVID may also include dysregulation of cytokines/chemokines, deficiencies in the innate immune response, and autoimmunity. This suggests that therapeutic attempts with drugs targeting cytokine-mediated inflammation in peripheral organs could also positively affect neuro-COVID manifestations. As a matter of fact, some of these drugs have also been scrutinized for their potential efficacy in treating neuroinflammatory diseases such as optic neuromyelitis, epilepsy, stroke, and traumatic brain injury, among others. On the other hand, anti-cytokine drugs, by impairing relevant physiological activities exerted by these mediators in the CNS, may also be endowed with significant neurological risk. Therefore, the primary aim of the present manuscript is to review the available preclinical and clinical data regarding the neurological effects of the drugs targeting cytokine-mediated inflammation, in order to raise awareness about their potentially beneficial or detrimental neurological consequences when used to treat COVID-19 patients.
Background and Purpose: Pancreatic cancer is an exceptionally fatal disease. However, therapeutic drugs for pancreatic cancer have presented a serious shortage over the past few decades. Signal Transducer and Activator of Transcription-3 (STAT3) is persistently activated in many human cancers where it promotes tumor development and progression. Natural products serve as an inexhaustible source of anticancer drugs. Here, we identified the natural product Trienomycin A (TA), an ansamycin antibiotic, as a potential inhibitor of the STAT3 pathway with potent activity against pancreatic cancer. Experimental Approach: Utilizing the STAT3-luciferase (STAT3-luc) reporter system, we found that TA potently inhibits the transcriptional activity of STAT3. We subsequently investigated in vitro and in vivo inhibitory activity of TA against pancreatic cancer and its potential mechanism by using the molecular docking, SPR assay, MTS assay, colony formation assay, transwell migration/invasion assay, flow cytometric analysis, immunofluorescence staining, quantitative real-time PCR, western blotting, tumor xenograft model, H&E staining and immunohistochemistry. Key Results: TA directly bound to STAT3 and inhibited STAT3 (Tyr705) phosphorylation, leading to the inhibition of the STAT3 pathway. TA significantly inhibited the colony formation, proliferation, migration and invasion of pancreatic cancer cell lines. TA dramatically blocked pancreatic tumor growth. More importantly, TA did not show obvious toxicity at the effective dose in mice. Conclusions and Implications: TA exhibits antineoplastic activity by suppressing the STAT3 activation in pancreatic cancer. TA could be a novel therapeutic candidate for pancreatic cancer by blocking the STAT3 pathway.
Background and Purpose: Cigarette smoking (CS) is the major risk factor for developing COPD and related skeletal muscle dysfunction. It has been postulated that CS exposure may directly causes muscle dysfunction via the induction of oxidative stress. The present study examined the effect of a potent Nox inhibitor and ROS scavenger, apocynin on CS-induced muscle dysfunction. Experimental Approach: Male BALB/c mice were exposed to either room air (sham) or CS generated from 9 cigarettes per day, 5 days a week for 8 weeks with or without apocynin treatment (5 mg·kg-1 w/v, intraperitoneal injection). C2C12 myotubes exposed to either hydrogen peroxide (H2O2) or water-soluble cigarette smoke extract (CSE) with or without apocynin (500 nM), was set up as an experimental model in vitro. Key Results: Eight weeks of CS exposure caused significant lung inflammation and muscle dysfunction in mice; evidenced by a 10% loss in muscle mass and 54% loss in contractile function of tibialis anterior, attributable to altered myogenic homeostasis and protein oxidation. These effects were prevented by apocynin administration. In C2C12 myotubes, direct exposure to H2O2 or CSE caused myofiber wasting, which was associated with altered myogenic homeostasis marked by ~50% loss in muscle-derived insulin-like growth factor (IGF)-1 and 1.5-fold increase in myostatin expression. Apocynin treatment completely attenuated CSE-induced Nox2 expression, preserving muscle-derived IGF-1 expression and downstream mammalian target of rapamycin (mTOR) signaling pathway, thereby preventing myofiber wasting. Conclusion and Implications: Targeted pharmacological inhibition of Nox-derived ROS may alleviate the lung and systemic manifestations in smokers with COPD.
Background: Vascular TRPV channels have emerged as important regulators of vascular tone. TRPV1 and endothelin-1 (ET-1) are independently associated with the pathophysiology of coronary vasospasm but the relationship between their vasomotor functions remains unclear. We characterized the vasomotor function of TRPV1 channels in human arterioles and investigated regulation of their vasomotor function by ET-1. Approach: Arterioles were threaded on two metal wires, equilibrated in a physiological buffer at 37 oC and exposed to increasing concentrations of capsaicin in the absence or presence of SB366791 (TRPV1-selective inhibitor) or GF109203X (PKC-selective inhibitor). Some arterioles were preconstricted with ET-1 or phenylephrine or high K+ buffer. TRPV1 mRNA and protein expression in human arteries were assessed. Results: TRPV1 transcripts and proteins were detected in human resistance arteries. Capsaicin (1 µM) induced concentration-dependent constriction of endothelium-intact (35 ± 8 %) and endothelium-denuded (43 ± 11 %) human adipose arterioles (HAA), which was significantly inhibited by SB366791 (0.2 ± 0.1 %). Preconstriction of HAA with ET-1, but not high potassium buffer or phenylephrine, significantly potentiated capsaicin-induced constriction (33 ± 7 % vs 12 ± 8 %). GF109203X significantly inhibited potentiation of capsaicin-induced constriction by ET-1. Conclusion: TRPV1 channels are expressed in the human vasculature and can influence vascular tone of human arterioles upon activation. Their vasomotor function is modulated by ET-1, mediated in part by PKC.. These findings reveal a novel interplay between ET-1 signaling and TRPV1 channels in human VSMC, adding to our understanding of the ion channel mechanisms that regulate human arteriolar tone and may also contribute to the pathophysiology of coronary vasospasm.
Background and Purpose The cyclic nucleotides cAMP and cGMP are ubiquitous second messengers participating in the regulation of several biological processes. Interference of cNMP signalling is linked to multiple diseases and thus is an important component of pharmaceutical research. The existing optogenetic toolbox in C. elegans is restricted to soluble adenylyl cyclases, the membrane-bound Blastocladiella CyclOp and hyperpolarizing rhodopsins, yet missing are membrane-bound photoactivatable adenylyl cyclases and hyperpolarizers on the basis of K+-currents. Experimental Approach For the characterization of the photoactivatable nucleotidyl cyclases, we expressed the proteins alone or in combination with cyclic-nucleotide gated channels in C. elegans muscle cells and cholinergic motor neurons. To investigate the extent of optogenetic cNMP production and the ability of the systems to de- or hyperpolarize the cells, we performed behavioural analyses (locomotion, muscle contraction) and measured the cNMP content in vitro. Key Results We implemented Catenaria CyclOp as a new tool for cGMP production, allowing fine-control of cGMP levels. As photoactivatable membrane-bound adenylyl cyclases, we established YFP::BeCyclOp(A-2x) and YFP::CaCyclOp(A-2x), enabling more specific optogenetic cAMP signalling compared to soluble ACs. For the hyperpolarization of excitable cells by K+-currents, we introduced the cAMP-gated K+-channel SthK from Spirochaeta thermophila with either bPAC or BeCyclOp(A-2x), and the Blastocladiella emersonii cGMP-gated K+-channel BeCNG1 with BeCyclOp. Conclusion and Implications We established a comprehensive suite of optogenetic tools for cNMP manipulation for the nematode, which will be useful for applications in many cell types, including sensory neurons which use mainly cGMP as second messenger, and for potent hyperpolarization using K+-ions.
Background and Purpose: The activation of the defense reaction inhibits the baroreflex response through the B3 and nucleus tractus solitarius (NTS) regions. Our aim was to determine whether and how baroreflex inhibition induced by the disinhibition of the rostral cuneiform nucleus, part of the defense pathway, involves serotonin cells in B3 and 5-HT3 receptors in the NTS. Experimental Approach: We performed immunohistochemistry and anatomical experiments to determine whether raphe serotonin cells expressing Fos were directly targeted by the rostral cuneiform nucleus. The effect of blocking raphe serotonin transmission and NTS 5-HT3 receptors, on cuneiform-induced inhibition of the baroreflex cardiac response, were also analyzed. Key Results: Bicuculline microinjected into the rostral cuneiform nucleus induced an increase of double labeled Fos-5-HT IR cells in both the LPGi and Raphe Magnus. The anterograde tracer Phaseolus vulgaris leucoaggutinin into the rostral cuneiform nucleus revealed a dense projection to the LPGi but not Raphe Magnus. Cuneiform-induced baroreflex inhibition was prevented by B3 injection of 8-OH-DPAT, a specific agonist for 5-HT1A receptors. Cuneiform disinhibition also failed to inhibit the baroreflex bradycardia after microinjection of a 5-HT3 receptor antagonist (granisetron) into the NTS or in 5-HT3 receptor knock-out mice. Conclusion and Implications: In conclusion, the rostral cuneiform nucleus participates in the defense inhibition of the baroreflex bradycardia via direct activation of the LPGi and a relay to the Raphe Magnus, to activate NTS 5-HT3 receptors and inhibit second-order baroreflex neurons. These data bring new insights in primary and secondary mechanisms involved in vital baroreflex prevention during stress.