In Vitro and In Vivo Pharmacological Profiles of LENART01, a Dermorphin-Ranatensin Hybrid Peptide.

Diverse chemical and pharmacological strategies are currently being explored to minimize the unwanted side effects of currently used opioid analgesics while achieving effective pain relief. The use of multitarget ligands with activity at more than one receptor represents a promising therapeutic approach. We recently reported a bifunctional peptide-based hybrid LENART01 combining dermorphin and ranatensin pharmacophores, which displays activity to the mu-opioid receptor (MOR) and dopamine D2 receptor (D2R) in rat brains and spinal cords. In this study, we investigated the in vitro binding and functional activities to the human MOR and the in vivo pharmacology of LENART01 in mice after subcutaneous administration. In vitro binding assays showed LENART01 to bind and be selective to the human MOR over the other opioid receptor subtypes and delta, kappa and nociceptin receptors. In the [35S]GTPγS binding assay, LENART01 acted as a potent and full agonist to the human MOR. In mice, LENART01 produced dose-dependent antinociceptive effects in formalin-induced inflammatory pain, with increased potency than morphine. Antinociceptive effects were reversed by naloxone, indicating MOR activation in vivo. Behavioral studies also demonstrated LENART01's properties to induce less adverse effects without locomotor dysfunction and withdrawal syndrome compared to conventional opioid analgesics, such as morphine. LENART01 is the first peptide-based MOR-D2R ligand known to date and the first dual MOR-dopamine D2R ligand for which in vivo pharmacology is reported with antinociceptive efficacy and reduced opioid-related side effects. Our current findings may pave the way to new pain therapeutics with limited side effects in acute and chronic use.

Opioid/Dopamine Receptor Binding Studies, NMR and Molecular Dynamics Simulation of LENART01 Chimera, an Opioid-Bombesin-like Peptide.

The design and development of hybrid compounds as a new class of drug candidates remains an excellent opportunity to improve the pharmacological properties of drugs (including enzymatic stability, efficacy and pharmacokinetic and pharmacodynamic profiles). In addition, considering various complex diseases and/or disorders, the conjugate chemistry approach is highly acceptable and justified. Opioids have long been recognized as the most potent analgesics and serve as the basic pharmacophore for potent hybrid compounds that may be useful in pain management. However, a risk of tolerance and physical dependence exists. Since dopamine receptors have been implicated in the aforementioned adverse effects of opioids, the construction of a hybrid with dual action at opioid and dopamine receptors is of interest. Herein, we present nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics simulation results for LENART01, an opioid-ranatensin hybrid peptide. Apart from molecular docking, protein-ligand interactions were also assessed in vitro using a receptor binding assay, which proved LENART01 to be bound to mu-opioid and dopamine receptors, respectively.

Bombesins: A New Frontier in Hybrid Compound Development.

Recently, bombesin (BN) and its analogs have attracted much attention as excellent anticancer agents because they interact with specific receptors widely distributed on the surface of various cancer cells. However, their biological properties proceed far beyond this, given a broad spectrum of activity. Bombesin receptor ligands are effective drugs for the treatment of rheumatoid arthritis or gastrointestinal diseases. However, most diseases are complex, and the use of polytherapy may lead to pharmacokinetic and pharmacodynamic drug-drug interactions, resulting in side effects. Therefore, there is a need to develop effective compounds that also contain BN or its analogs, which are combined with other structural entities, thus generating a so-called hybrid drug. Hybrid drugs that contain bombesin pharmacophore(s) may be proposed as a solution to the problem of polytherapy or the lack of an effective cure. Such structures have now demonstrated the desired efficacy, though information on these aforementioned compounds is relatively scarce. Therefore, our paper aims to encourage researchers to focus on bombesins. Herein, we indicate that the hybrid approach should also be firmly applied to bombesins and the BN receptor family. This paper's structure is divided into two main sections demonstrating bombesins and their properties, as well as recent data on bombesin-based hybrid compounds and their potential usefulness in medicine. Overall, it refers to the discovery and synthesis of modified bombesin-based hybrid compounds.

Evaluation of Antimicrobial Activities against Various E. coli Strains of a Novel Hybrid Peptide-LENART01.

Finding the ideal antimicrobial drug with improved efficacy and a safety profile that eliminates antibiotic resistance caused by pathogens remains a difficult task. Indeed, there is an urgent need for innovation in the design and development of a microbial inhibitor. Given that many promising antimicrobial peptides with excellent broad-spectrum antibacterial properties are secreted by some frog species (e.g., bombesins, opioids, temporins, etc.), our goal was to identify the antimicrobial properties of amphibian-derived dermorphin and ranatensin peptides, which were combined to produce a hybrid compound. This new chimera (named LENART01) was tested for its antimicrobial activity against E. coli strains K12 and R1-R4, which are characterized by differences in lipopolysaccharide (LPS) core oligosaccharide structure. The results showed that LENART01 had superior activity against the R2 and R4 strains compared with the effects of the clinically available antibiotics ciprofloxacin or bleomycin (MIC values). Importantly, the inhibitory effect was not concentration dependent; however, LENART01 showed a time- and dose-dependent hemolytic effect in hemolytic assays.

Air Pollution: A Silent Key Driver of Dementia.

In 2017, the Lancet Commission on Dementia Prevention, Intervention, and Care included air pollution in its list of potential risk factors for dementia; in 2018, the Lancet Commission on Pollution concluded that the evidence for a causal relationship between fine particulate matter (PM) and dementia is encouraging. However, few interventions exist to delay or prevent the onset of dementia. Air quality data are becoming increasingly available, and the science underlying the associated health effects is also evolving rapidly. Recent interest in this area has led to the publication of population-based cohort studies, but these studies have used different approaches to identify cases of dementia. The purpose of this article is to review recent evidence describing the association between exposure to air pollution and dementia with special emphasis on fine particulate matter of 2.5 microns or less. We also summarize here the proposed detailed mechanisms by which air pollutants reach the brain and activate the innate immune response. In addition, the article also provides a short overview of existing limitations in the treatment of dementia.

Antipsychotic Drugs Efficacy in Dextromethorphan-Induced Psychosis.

Psychosis is known as a broad term of symptoms that cause serious disorganization of behavior, thinking, and perception of reality. One of the medicines that recently gained much attention in terms of its psychotic potential is dextromethorphan (DXM). DXM, a widely used antitussive drug, is a commonly abused drug because of its euphoric, hallucinogenic, and dissociative properties. To date, DXM is a legally marketed cough suppressant that is neither a controlled substance nor a regulated chemical under the Controlled Substances Act. The management of DXM-related psychosis is dependent on the type of psychotic symptoms. Atypical neuroleptics (i.e., olanzapine, risperidone, quetiapine) and typical haloperidol have been used in symptomatic treatment due to their efficacy, especially in positive symptoms (hallucinations and delusions). These agents are also recognized as the preferred option in the symptomatic treatment of DXM-related psychosis due to their better efficacy and safety profile than typical haloperidol in the short-term course. The focus of the present review concerns the current stage of knowledge about DXM psychotic potency as well as the management of DXM-related psychoses with a special emphasis on atypical antipsychotic drugs (i.e., olanzapine, risperidone, quetiapine, and haloperidol).

The Role of a Natural Amphibian Skin-Based Peptide, Ranatensin, in Pancreatic Cancers Expressing Dopamine D2 Receptors.

Despite the progress in early diagnostic and available treatments, pancreatic cancer remains one of the deadliest cancers. Therefore, there is an urgent need for novel anticancer agents with a good safety profile, particularly in terms of possible side-effects. Recently dopaminergic receptors have been widely studied as they were proven to play an important role in cancer progression. Although various synthetic compounds are known for their interactions with the dopaminergic system, peptides have recently made a great comeback. This is because peptides are relatively safe, easy to correct in terms of the improvement of their physicochemical and biological properties, and easy to predict. This paper aims to evaluate the anticancer activity of a naturally existing peptide-ranatensin, toward three different pancreatic cancer cell lines. Additionally, since there is no sufficient information confirming the exact character of the interaction between ranatensin and dopaminergic receptors, we provide, for the first time, binding properties of the compound to such receptors.

Comparative Study of Chemical Stability of a PK20 Opioid-Neurotensin Hybrid Peptide and Its Analogue [Ile9]PK20-The Effect of Isomerism of a Single Amino Acid.

Chemical stability is one of the main problems during the discovery and development of potent drugs. When ignored, it may lead to unreliable biological and pharmacokinetics data, especially regarding the degradation of products' possible toxicity. Recently, two biologically active drug candidates were presented that combine both opioid and neurotensin pharmacophores in one entity, thus generating a hybrid compound. Importantly, these chimeras are structurally similar except for an amino acid change at position 9 of the peptide chain. In fact, isoleucine (C6H13NO2) was replaced with its isomer tert-leucine. These may further lead to various differences in hybrids' behavior under specific conditions (temperature, UV, oxidative, acid/base environment). Therefore, the purpose of the study is to assess and compare the chemical stability of two hybrid peptides that differ in nature by way of one amino acid (tert-leucine vs. isoleucine). The obtained results indicate that, opposite to biological activity, the substitution of tert-leucine into isoleucine did not substantially influence the compound's chemical stability. In fact, neither hydrolysis under alkaline and acidic conditions nor oxidative degradation resulted in spectacular differences between the two compounds-although the number of potential degradation products increased, particularly under acidic pH. However, such a modification significantly reduced the compound's half-life from 204.4 h (for PK20 exposed to 1M HCl) to 117.7 h for [Ile9]PK20.

Anticancer efficacy of endo- and exogenous potent ligands acting at dopaminergic receptor-expressing cancer cells.

Cancer is one of the most common and dreaded diseases affecting the vastness of society. Unfortunately, still some people die especially when cancer is not diagnosed and thus caught early enough. On the other hand, using available chemo- or radiotherapy may result in serious side effects. Therefore, cancer-specific medications seem to be the most desired and safe therapy. Knowing that some cancers are characterized by overexpression of specific receptors on the cell surface, target-mediated drugs could serve as a unique and effective form of therapy. In line with this, recently dopaminergic receptors were presented important in cancer therapy as several dopaminergic ligands revealed their efficacy in tumor growth reduction as well as in apoptosis mediation. Unfortunately, the indication of whether DA receptor agonists or antagonists are the best choices in cancer treatment is quite difficult, since both of them may exert either pro- or anticancer effects. In this review, we analyze the therapeutic efficacy of compounds, both of exogenous and endogenous origin, targeting dopaminergic receptor-expressing cancers.

The Lactoferrin Phenomenon-A Miracle Molecule.

Numerous harmful factors that affect the human body from birth to old age cause many disturbances, e.g., in the structure of the genome, inducing cell apoptosis and their degeneration, which leads to the development of many diseases, including cancer. Among the factors leading to pathological processes, microbes, viruses, gene dysregulation and immune system disorders have been described. The function of a protective agent may be played by lactoferrin as a "miracle molecule", an endogenous protein with a number of favorable antimicrobial, antiviral, antioxidant, immunostimulatory and binding DNA properties. The purpose of this article is to present the broad spectrum of properties and the role that lactoferrin plays in protecting human cells at all stages of life.

Lactoferrin as a Human Genome "Guardian"-An Overall Point of View.

Structural abnormalities causing DNA modifications of the ethene and propanoadducts can lead to mutations and permanent damage to human genetic material. Such changes may cause premature aging and cell degeneration and death as well as severe impairment of tissue and organ function. This may lead to the development of various diseases, including cancer. In response to a damage, cells have developed defense mechanisms aimed at preventing disease and repairing damaged genetic material or diverting it into apoptosis. All of the mechanisms described above are part of the repertoire of action of Lactoferrin-an endogenous protein that contains iron in its structure, which gives it numerous antibacterial, antiviral, antifungal and anticancer properties. The aim of the article is to synthetically present the new and innovative role of lactoferrin in the protection of human genetic material against internal and external damage, described by the modulation mechanisms of the cell cycle at all its levels and the mechanisms of its repair.

Chimeric Structures in Mental Illnesses-"Magic" Molecules Specified for Complex Disorders.

Mental health problems cover a wide spectrum of diseases, including mild to moderate anxiety, depression, alcohol/drug use disorders, as well as bipolar disorder and schizophrenia. Pharmacological treatment seems to be one of the most effective opportunities to recover function efficiently and satisfactorily. However, such disorders are complex as several target points are involved. This results in a necessity to combine different types of drugs to obtain the necessary therapeutic goals. There is a need to develop safer and more effective drugs. Considering that mental illnesses share multifactorial processes, the paradigm of one treatment with multiple modes of action rather than single-target strategies would be more effective for successful therapies. Therefore, hybrid molecules that combine two pharmacophores in one entity show promise, as they possess the desired therapeutic index with a small off-target risk. This review aims to provide information on chimeric structures designed for mental disorder therapy (i.e., schizophrenia and depression), and new types of drug candidates currently being tested. In addition, a discussion on some benefits and limitations of multifunctional, bivalent drug candidates is also given.

Mitochondrial Oxidative Stress-A Causative Factor and Therapeutic Target in Many Diseases.

The excessive formation of reactive oxygen species (ROS) and impairment of defensive antioxidant systems leads to a condition known as oxidative stress. The main source of free radicals responsible for oxidative stress is mitochondrial respiration. The deleterious effects of ROS on cellular biomolecules, including DNA, is a well-known phenomenon that can disrupt mitochondrial function and contribute to cellular damage and death, and the subsequent development of various disease processes. In this review, we summarize the most important findings that implicated mitochondrial oxidative stress in a wide variety of pathologies from Alzheimer disease (AD) to autoimmune type 1 diabetes. This review also discusses attempts to affect oxidative stress as a therapeutic avenue.

The Synthesis and Evaluation of Aminocoumarin Peptidomimetics as Cytotoxic Agents on Model Bacterial E. coli Strains.

This work presents the successful synthesis of a library of novel peptidomimetics via Ugi multicomponent reaction. Most of these peptidomimetics contain differently substituted aminocoumarin; 7-amino-4-methylcoumarin and 7-amino-4-(trifluoromethyl) coumarin. Inspired by the biological properties of coumarin derivatives and peptidomimetics, we proposed the synthesis of coumarin incorporated peptidomimetics. We studied the potential of synthesized compounds as antimicrobial drugs on model E. coli bacterial strains (k12 and R2-R4). To highlight the importance of coumarin in antimicrobial resistance, we also synthesized the structurally similar peptidomimetics, using benzylamine. Preliminary cellular studies suggest that the compounds with coumarin derivatives have more potential as antimicrobial agents compared to the compounds without coumarin. We also analyzed the effect of aldehyde, free acid group and ester group on the course of their antimicrobial properties.

Treatment with dopamine ß-hydroxylase (DBH) inhibitors prevents morphine use and relapse-like behavior in rats.

BACKGROUND: Opioid use disorders are serious contributors to the harms associated with the drug use. Unfortunately, therapeutic interventions for opioid addicts after detoxification have been limited and not sufficiently effective. Recently, several studies have led to promising results with disulfiram (DSF), a dopamine ß-hydroxylase (DBH) inhibitor, showing that it is a potent agent against not only alcohol but also addiction to various drugs. MATERIALS AND METHODS: This study was designed to examine whether DSF and nepicastat (NEP; another DBH inhibitor) modify morphine intake and reinstatement of seeking-behavior using the rat model of intravenous morphine self-administration. Additionally, we intended to estimate the effects of both inhibitors on the locomotor activity as well as on extracellular dopamine and its metabolite levels in the nucleus accumbens using microdialysis in naive rats. RESULTS: We demonstrated that both DBH inhibitors reduced responding to morphine self-administration. Moreover, DSF and NEP administered acutely before reinstatement test sessions consistently attenuated the reinforcing effects of morphine and a morphine-associated conditioned cue. The observed effects for lower doses (6.25-25 mg/kg; ip) of both DBH inhibitors seem to be independent of locomotor activity reduction and dopamine level in the nucleus accumbens. Neither DSF nor NEP administered daily during morphine abstinence with extinction training sessions had any effect on active lever-responding and changed the reinstatement induced by morphine priming doses. Reinstatement of drug-seeking behavior induced by a conditioned cue previously associated with morphine delivery was attenuated following repeated administration of DSF or NEP during the abstinence period. CONCLUSION: These results seem to point to the significance  of DBH inhibition as a potential pharmacotherapy against morphine use disorders.

Nitric oxide modulates tapentadol antinociceptive tolerance and physical dependence.

Tapentadol, an analgesic with a dual mechanism of action, involving both µ-opioid receptor agonism and noradrenaline reuptake inhibition (MOP-NRI), was designed for the treatment of moderate to severe pain. However, the widely acknowledged risk of analgesic tolerance and development of physical dependence following sustained opioid use may hinder their effectiveness. One of the possible mechanisms behind these phenomena are alterations in nitric oxide synthase (NOS) system activity. The aim of the study was to investigate the tolerance and dependence potential of tapentadol in rodent models and to evaluate the possible role of nitric oxide (NO) in these processes. Our study showed that chronic tapentadol treatment resulted in tolerance to its antinociceptive effects to an extent similar to tramadol, but much less than morphine. A single injection of a non-selective NOS inhibitor, NG-nitro-L-arginine (L-NOArg), reversed the tapentadol tolerance. In dependence studies, repeated administration of L-NOArg attenuated naloxone-precipitated withdrawal in tapentadol-treated mice, whereas a single injection of L-NOArg was ineffective. Biochemical analysis revealed that tapentadol decreased nNOS protein levels in the dorsal root ganglia of rats following 31 days of treatment, while no significant changes were found in iNOS and eNOS protein expression. Moreover, pre-treatment with L-NOArg augmented tapentadol antinociception in an opioid- and α2-adrenoceptor-dependent manner. In conclusion, our data suggest that the NOS system plays an important role in the attenuation of tapentadol-induced tolerance and withdrawal. Thus, inhibition of NOS activity can serve as a promising treatment option for long-term tapentadol use by extending its effectiveness and improving the side-effects profile.

Advantages and disadvantages of disulfiram coadministered with popular addictive substances.

Disulfiram (DSF) is a well-known anti-alcohol agent that inhibits aldehyde dehydrogenase and results in extreme 'hangover' symptoms when consumed with alcohol. This drug, however, has been suggested as useful in other forms of drug addiction due to its beneficial potential in both drug abuse reduction and withdrawal. However, among other drugs used in alcohol dependence, it carries the greatest risk of pharmacological interactions. Concomitant use of DSF and central nervous system stimulants usually leads to harmful, undesirable effects. To date, there is still limited data regarding the detailed safety profile of DSF as a concomitant drug. In this review article, we outline the current state of knowledge about DSF, its broad pharmacological action, as well as therapeutic effects, with a particular emphasis on the molecular understanding of its potential pharmacodynamic interactions with common addictive substances (e.g., alcohol, cocaine, cannabinoids, opioids) supported by relevant examples.

Contribution of opioid and neurotensin receptors in the anti-inflammatory activity of PK20 hybrid compound in murine airways.

PK20 is an anti-inflammatory hybrid compound, composed of an endomorphin-2-like and neurotensin-like fragments. The aim of the present study is to assess the contribution of particular pharmacophores to the activity of the hybrid tested. For this purpose, airway hyperresponsiveness, accumulation of inflammatory cells in bronchoalveolar lavage fluid (BALF), concentration of mouse mast cell protease, malondialdehyde and secretory phospholipase 2 activity in lung tissue, as well as production of pro-inflammatory cytokines in BALF and lung were determined by using murine model of non-atopic asthma. Blocking either neurotensin receptors or mu opioid receptors did not alter the potential of PK20 in reducing airway hyperresponsiveness. In studies of inflammatory cells, the beneficial effect of the entire peptide occurs to be mediated by the stimulation of neurotensin receptors. However, regarding cytokine and biochemical assays, pretreatment with both receptor antagonists resulted in a different effect on its activity depending on the parameter studied. To conclude, the activation of both the opioid and neurotensin receptors seems to be necessary to induce the full anti-inflammatory activity of the hybrid compound.

Poly(chitosan-ester-ether-urethane) Hydrogels as Highly Controlled Genistein Release Systems.

Polymeric hydrogels play an increasingly important role in medicine, pharmacy and cosmetology. They appear to be one of the most promising groups of biomaterials due to their favorable physicochemical properties and biocompatibility. The objective of the presented study was to synthesize new poly(chitosan-ester-ether-urethane) hydrogels and to study the kinetic release of genistein (GEN) from these biomaterials. In view of the above, six non-toxic hydrogels were synthesized via the Ring-Opening Polymerization (ROP) and polyaddition processes. The poly(ester-ether) components of the hydrogels have been produced in the presence of the enzyme as a biocatalyst. In some cases, the in vitro release rate of GEN from the obtained hydrogels was characterized by near-zero-order kinetics, without "burst release" and with non-Fickian transport. It is important to note that developed hydrogels have been shown to possess the desired safety profile due to lack of cytotoxicity to skin cells (keratinocytes and fibroblasts). Taking into account the non-toxicity of hydrogels and the relatively highly controlled release profile of GEN, these results may provide fresh insight into polymeric hydrogels as an effective dermatological and/or cosmetological tool.

The Positive and Negative Outcome of Morphine and Disulfiram Subacute Co-Administration in Rats in the Absence of Ethanol Challenge.

Recently, a well-known anti-alcohol agent, disulfiram (DSF), has gain much interest, as it was found to be effective in the treatment of cocaine abusers, thus also giving hope for patients addicted to opioids and other illicit drugs. Therefore, this study was aimed to investigate the possible outcome that might occur within the subacute co-administration of both morphine (MRF) and DSF in rats, but in the absence of ethanol challenge. As observed, intraperitoneal DSF dose-dependently enhanced MRF-mediated analgesia with the maximal efficacy at a dose of 100 mg/kg. Furthermore, MRF-induced tolerance and aggressive behavior were significantly reduced by DSF (100 mg/kg, i.p.) in comparison to MRF solely. Nonetheless, significant blood biochemical markers of hepatotoxicity were found (i.e., alteration in the levels of glutathione, blood urea nitrogen, etc.), following a combination of both drugs. Likewise, histological analysis of liver tissue revealed severe changes in the group of DSF + MRF, which includes swelling, cell death, damage to certain vessels, and hemorrhages into the liver parenchyma. Our findings indicate that DSF should be used with extreme caution, especially within the course of subacute concomitant use with MRF, as several possible side effects may take place.