Probenecid, an Old Drug with Potential New Uses for Central Nervous System Disorders and Neuroinflammation

An overview of progress in human metapneumovirus (hMPV) research: Structure, function, and therapeutic opportunities

The human metapneumovirus (hMPV), a member of the Pneumoviridae family, is a significant respiratory pathogen that causes severe infections in infants, children, the elderly, adults with chronic illnesses, and individuals with immunocompromised conditions. Globally, hMPV is recognized as the second leading cause of bronchiolitis and pneumonia among children under five. The absence of targeted antiviral treatments or vaccines for hMPV significantly strains the global health-care system. This review summarizes recent advances and scientific findings on hMPV by reviewing the current literature on its life cycle, structure, function, prevention, and treatment options.

Pannexin 1 channels: A bridge between synaptic plasticity and learning and memory processes

The Pannexin 1 channel is a membrane protein widely expressed in various vertebrate cell types, including microglia, astrocytes, and neurons within the central nervous system. Growing research has demonstrated the significant involvement of Panx1 in synaptic physiology, such as its contribution to long-term synaptic plasticity, with a particular focus on the hippocampus, an essential structure for learning and memory. Investigations studying the role of Panx1 in synaptic plasticity have utilized knockout animal models and channel inhibition techniques, revealing that the absence or blockade of Panx1 channels in this region promotes synaptic potentiation, dendritic arborization, and spine formation. Despite substantial progress, the precise mechanism by which Panx1 regulates synaptic plasticity remains to be determined. Nevertheless, evidence suggests that Panx1 may exert its influence by releasing signaling molecules, such as adenosine triphosphate (ATP), or through the clearance of endocannabinoids (eCBs). This review aims to comprehensively explore the current literature on the role of Panx1 in synapses. By examining relevant articles, we seek to enhance our understanding of Panx1's contribution to synaptic fundamental processes and the potential implications for cognitive function.

A chemoselective hydroxycarbonylation and 13C-labeling of aryl diazonium salts using formic acid as the C-1 source

We report a one-pot synthesis of aryl carboxylic acids utilizing HCOOH as a CO surrogate with low Pd-catalyst loading. This operationally simple and scalable method does not require use of a high-pressure reactor, two-chamber reaction vessel, phosphine ligand, or base and proceeds in a relatively short amount of time at ambient temperature. Notably, halides, including iodo and bromo groups, and nitro groups remain intact under these mild reaction conditions. This methodology has been successfully applied to synthesizing 13C-labeled aryl carboxylic acids with satisfactory yields.

The challenging inhibition of Aldose Reductase for the treatment of diabetic complications: a 2019-2023 update of the patent literature

INTRODUCTION

Aldose reductase (AKR1B1, EC: 1.1.1.21) is a recognized target for the treatment of long-term diabetic complications since its activation in hyperglycemia and role in the polyol pathway. In particular, the tissue-specificity of AKR1B1 expression makes the design of the traditional Aldose Reductase Inhibitors (ARIs) and the more recent Aldose Reductase Differential Inhibitors (ARDIs) exploitable strategies to treat pathologies resulting from diabetic conditions.

AREAS COVERED

A brief overview of the roles and functions of AKR1B1 along with known ARIs and ARDIs was provided. Then, the design of the latest inhibitors in the scientific scenario was discussed, aiming at introducing the research achievement in the field of intellectual properties. Patents dealing with AKR1B1 and diabetes filed in the 2019-2023 period were collected and analyzed. Reaxys, Espacenet, SciFindern, and Google Patents were surveyed, using 'aldose reductase' and 'inhibitor' as the reference keywords. The search results were then filtered by PRISMA protocol, thus obtaining 16 records to review.

EXPERT OPINION

Although fewer in number than in the early 2000s, patent applications are still being filed in the field of ARIs, with a large number of Chinese inventors reporting new synthetic ARIs in favor of the repositioning approach.

Overview of pro-inflammatory and pro-survival components in neuroinflammatory signalling and neurodegeneration

Neurodegenerative diseases (NDDs) are identified by the progressive deterioration of neurons and a subsequent decline in cognitive function, creating an enormous burden on the healthcare system globally. Neuroinflammation is an intricate procedure that initiates the immune response in the central nervous system (CNS) and significantly impacts the expansion of NDDs. This study scrutinizes the complicated interaction between neuronal degeneration and neuroinflammation, with an appropriate emphasis on their reciprocal impacts. It also describes how neuroinflammatory reactions in NDDs are controlled by activating certain pro-inflammatory transcription factors, including p38 MAPK, FAF1, Toll-like receptors (TLRs), and STAT3. Alternatively, it evaluates the impact of pro-survival transcription factors, such as the SOCS pathway, YY1, SIRT1, and MEF2, which provide neuroprotective protection against damage triggered by neuroinflammation. Moreover, we study the feasibility of accommodating drug repositioning as a therapeutic approach for treating neuroinflammatory disorders. This suggests the use of existing medications for novel utilization in the treatment of NDDs. Furthermore, the study intends to reveal novel biomarkers of neuroinflammation that contribute fundamental observation for the initial detection and diagnosis of these disorders. This study aims to strengthen therapy interference and augment patient outcomes by combining ongoing data and evaluating novel therapeutic and diagnostic approaches. The goal is to devote the growth of an effective strategy to reducing the impact of neuroinflammation on neuronal protection in NDDs.

Inhibition of the NMDA Currents by Probenecid in Amygdaloid Kindling Epilepsy Model

Epilepsy is characterized by a sustained depolarization and repeated discharge of neurons, attributed to overstimulation of N-methyl-D-aspartate receptors (NMDAr). Herein, we propose that probenecid (PROB), an inhibitor of the activity of some ATP binding-cassette transporters (ABC-transporters) can modify NMDAr activity and expression in amygdaloid kindled model. Some studies have suggested that NMDAr expression could be regulated by inhibiting the activity of P-glycoprotein (MDR1) and drug resistance protein-1 (MRP1). Besides, PROB was found to interact with other proteins with proven activity in the kindling model, such as TRPV2 channels, OAT1, and Panx1. Administering PROB at two doses (100 and 300 mg/kg/d) for 5 d decreased after-discharge duration and Racine behavioral scores. It also reduced the expression of NR2B and the activity of total NOS and the expression of nNOS with respect to the kindling group. In a second protocol, voltage-clamp measurements of NMDA-evoked currents were performed in CA1 hippocampal cells dissociated from control and kindled rats. PROB produced a dose-dependent reduction in NMDA-evoked currents. In neurons from kindled rats, a residual NMDA-evoked current was registered with respect to control animals, while a reduction in NMDA-evoked currents was observed in the presence of 20 mM PROB. Finally, we evaluated the expression of MRP1 and MDR1 in order to establish a relationship between the reduction of kindling parameters, the inhibition of NMDA-type currents, and the expression of these transporters. Based on our results, we conclude that at the concentrations used, PROB inhibits currents evoked by NMDA in dissociated neurons of control and kindled rats. In the kindling model, at the tested doses, PROB decreases the after-discharge duration and Racine behavioral score in the kindling model. We propose a mechanism that could be dependent on the expression of ABC-type transporters.

Spatiotemporally selective astrocytic ATP dynamics encode injury information sensed by microglia following brain injury in mice

Injuries to the brain result in tunable cell responses paired with stimulus properties, suggesting the existence of intrinsic processes that encode and transmit injury information; however, the molecular mechanism of injury information encoding is unclear. Here, using ATP fluorescent indicators, we identify injury-evoked spatiotemporally selective ATP dynamics, Inflares, in adult mice of both sexes. Inflares are actively released from astrocytes and act as the internal representations of injury. Inflares encode injury intensity and position at their population level through frequency changes and are further decoded by microglia, driving changes in their activation state. Mismatches between Inflares and injury severity lead to microglia dysfunction and worsening of injury outcome. Blocking Inflares in ischemic stroke in mice reduces secondary damage and improves recovery of function. Our results suggest that astrocytic ATP dynamics encode injury information and are sensed by microglia.

Probenecid Inhibits Human Metapneumovirus (HMPV) Replication In Vitro and in BALB/c Mice

Human metapneumovirus (HMPV) is an important cause of acute respiratory tract infection and causes significant morbidity and mortality. There is no specific antiviral drug to treat HMPV or vaccine to prevent HMPV. This study determined if probenecid, a host-targeting antiviral drug, had prophylactic (pre-virus) or therapeutic (post-virus) efficacy to inhibit HMPV replication in LLC-MK2 cells in vitro and in the lungs of BALB/c mice. This study showed that ≥0.5 μM probenecid significantly inhibited HMPV replication in vitro, and 2-200 mg/kg probenecid prophylaxis or treatment reduced HMPV replication in BALB/c mice.

Evaluation of the inhibitory effects of antigout drugs on human carboxylesterases in vitro

Gout is an immune-metabolic disease that frequently coexists with multiple comorbidities such as chronic kidney disease, cardiovascular disease and metabolic syndrome, therefore, it is often treated in combination with these complications. The present study aimed to evaluate the inhibitory effect of antigout drugs (allopurinol, febuxostat, topiroxostat, benzbromarone, lesinurad and probenecid) on the activity of the crucial phase I drug-metabolizing enzymes, carboxylesterases (CESs). 2-(2-benzoyl-3-methoxyphenyl) benzothiazole (BMBT) and fluorescein diacetate (FD) were utilized as the probe reactions to determine the activity of CES1 and CES2, respectively, through in vitro culturing with human liver microsomes. Benzbromarone and lesinurad exhibited strong inhibition towards CESs with Ki values of 2.16 and 5.15 μM for benzbromarone towards CES1 and CES2, respectively, and 2.94 μM for lesinurad towards CES2. In vitro-in vivo extrapolation (IVIVE) indicated that benzbromarone and lesinurad might disturb the metabolic hydrolysis of clinical drugs in vivo by inhibiting CESs. In silico docking showed that hydrogen bonds and hydrophobic interactions contributed to the intermolecular interactions of antigout drugs on CESs. Therefore, vigilant monitoring of potential drug-drug interactions (DDIs) is imperative when co-administering antigout drugs in clinical practice.

Promising immunomodulators for management of substance and alcohol use disorders

INTRODUCTION

The neuroimmune system has emerged as a novel target for the treatment of substance use disorders (SUDs), with immunomodulation producing encouraging therapeutic benefits in both preclinical and clinical settings.

AREAS COVERED

In this review, we describe the mechanism of action and immune response to methamphetamine, opioids, cocaine, and alcohol. We then discuss off-label use of immunomodulators as adjunctive therapeutics in the treatment of neuropsychiatric disorders, demonstrating their potential efficacy in affective and behavioral disorders. We then discuss in detail the mechanism of action and recent findings regarding the use of ibudilast, minocycline, probenecid, dexmedetomidine, pioglitazone, and cannabidiol to treat (SUDs). These immunomodulators are currently being investigated in clinical trials described herein, specifically for their potential to decrease substance use, withdrawal severity, central and peripheral inflammation, comorbid neuropsychiatric disorder symptomology, as well as their ability to improve cognitive outcomes.

EXPERT OPINION

We argue that although mixed, findings from recent preclinical and clinical studies underscore the potential benefit of immunomodulation in the treatment of the behavioral, cognitive, and inflammatory processes that underlie compulsive substance use.

Age-Dependent Activation of Pannexin1 Function Contributes to the Development of Epileptogenesis in Autosomal Dominant Sleep-related Hypermotor Epilepsy Model Rats

To explore the processes of epileptogenesis/ictogenesis, this study determined the age-dependent development of the functional abnormalities in astroglial transmission associated with pannexin1-hemichannel using a genetic rat model of autosomal dominant sleep-related hypermotor epilepsy (ADSHE) named 'S286L-TG'. Pannexin1 expression in the plasma membrane of primary cultured cortical astrocytes and the orbitofrontal cortex (OFC), which is an ADSHE focus region, were determined using capillary immunoblotting. Astroglial D-serine releases induced by artificial high-frequency oscillation (HFO)-evoked stimulation, the removal of extracellular Ca2+, and the P2X7 receptor agonist (BzATP) were determined using ultra-high performance liquid chromatography (UHPLC). The expressions of pannexin1 in the plasma membrane fraction of the OFC in S286L-TG at four weeks old were almost equivalent when compared to the wild type. The pannexin1 expression in the OFC of the wild type non-statistically decreased age-dependently, whereas that in S286L-TG significantly increased age-dependently, resulting in relatively increasing pannexin1 expression from the 7- (at the onset of interictal discharge) and 10-week-old (after the ADSHE seizure onset) S286L-TG compared to the wild type. However, no functional abnormalities of astroglial pannexin1 expression or D-serine release through the pannexin1-hemichannels from the cultured astrocytes of S286L-TG could be detected. Acutely HFO-evoked stimulation, such as physiological ripple burst (200 Hz) and epileptogenic fast ripple burst (500 Hz), frequency-dependently increased both pannexin1 expression in the astroglial plasma membrane and astroglial D-serine release. Neither the selective inhibitors of pannexin1-hemichannel (10PANX) nor connexin43-hemichannel (Gap19) affected astroglial D-serine release during the resting stage, whereas HFO-evoked D-serine release was suppressed by both inhibitors. The inhibitory effect of 10PANX on the ripple burst-evoked D-serine release was more predominant than that of Gap19, whereas fast ripple burst-evoked D-serine release was predominantly suppressed by Gap19 rather than 10PANX. Astroglial D-serine release induced by acute exposure to BzATP was suppressed by 10PANX but not by Gap19. These results suggest that physiological ripple burst during the sleep spindle plays important roles in the organization of some components of cognition in healthy individuals, but conversely, it contributes to the initial development of epileptogenesis/ictogenesis in individuals who have ADSHE vulnerability via activation of the astroglial excitatory transmission associated with pannexin1-hemichannels.

Pannexin1: insight into inflammatory conditions and its potential involvement in multiple organ dysfunction syndrome

Sepsis represents a global health concern, and patients with severe sepsis are at risk of experiencing MODS (multiple organ dysfunction syndrome), which is associated with elevated mortality rates and a poorer prognosis. The development of sepsis involves hyperactive inflammation, immune disorder, and disrupted microcirculation. It is crucial to identify targets within these processes to develop therapeutic interventions. One such potential target is Panx1 (pannexin-1), a widely expressed transmembrane protein that facilitates the passage of molecules smaller than 1 KDa, such as ATP. Accumulating evidence has implicated the involvement of Panx1 in sepsis-associated MODS. It attracts immune cells via the purinergic signaling pathway, mediates immune responses via the Panx1-IL-33 axis, promotes immune cell apoptosis, regulates blood flow by modulating VSMCs' and vascular endothelial cells' tension, and disrupts microcirculation by elevating endothelial permeability and promoting microthrombosis. At the level of organs, Panx1 contributes to inflammatory injury in multiple organs. Panx1 primarily exacerbates injury and hinders recovery, making it a potential target for sepsis-induced MODS. While no drugs have been developed explicitly against Panx1, some compounds that inhibit Panx1 hemichannels have been used extensively in experiments. However, given that Panx1's role may vary during different phases of sepsis, more investigations are required before interventions against Panx1 can be applied in clinical. Overall, Panx1 may be a promising target for sepsis-induced MODS. Nevertheless, further research is needed to understand its complex role in different stages of sepsis fully and to develop suitable pharmaceutical interventions for clinical use.