Current Pharmaceutical Design - Volume 24, Issue 14, 2018

During the past decade, an abundance of new evidence highlighted the importance of inflammation in the development of chronic pathologies such as neurodegeneration, cancer, diabetes, cardiovascular disease and inflammatory bowel disease. However, most of the current therapies do not address the underlying problem and better therapies are urgently needed. A growing number of researchers have discovered various signaling pathways that are associated with the initiation and progression of inflammation. Among different pathways, we will focus on three classical inflammatory pathways: p38 MAPK, IL-6/JAK/STAT3 and PI3K; and a non-classical inflammatory pathway, the Hippo. Recently, the Hippo pathway has been linked to various inflammatory modulators such as FoxO1/3, TNFα, IL-6, COX2, HIF-1α, AP-1, JAK and STAT. In this review, the molecular mechanisms, associated pathologies and selected drugs (both preclinical and clinical) of these signaling pathways will be summarized. Finally, limitations and potential risks of anti-inflammatory drugs will also be discussed.

Traditionally neurological diseases have been classified, on the basis of their pathogenesis, into vascular, degenerative, inflammatory and traumatic diseases. Examples of the main inflammatory neurological diseases include multiple sclerosis, which is characterized by an immune-mediated response against myelin proteins, and meningoencephalitis, where the inflammatory response is triggered by infectious agents. However, recent evidence suggests a potential role of inflammatory mechanisms also in neurological conditions not usually categorized as inflammatory, such as Alzheimer's disease, Parkinson's disease, Huntington' disease, amyotrophic lateral sclerosis, stroke and traumatic brain injuries. The activation of glial cells and of complement-mediated pathways, the synthesis of inflammation mediators, and the recruitment of leukocytes are the key elements of secondary inflammatory injury following a wide spectrum of primary brain injuries. A better understanding of the role that inflammatory processes play in the natural history of diseases is essential in order to identify potential therapeutic targets and to develop integrated pharmacological approaches acting at different levels and stages of the diseases.

Alcohol consumption causes liver diseases, designated as Alcoholic Liver Disease (ALD). Because alcohol is detoxified by alcohol dehydrogenase (ADH), a major ethanol metabolism system, the development of ALD was initially believed to be due to malnutrition caused by alcohol metabolism in liver. The discovery of the microsomal ethanol oxidizing system (MEOS) changed this dogma. Cytochrome P450 enzymes (CYP) constitute the major components of MEOS. Cytochrome P450 2E1 (CYP2E1) in MEOS is one of the major ROS generators in liver and is considered to be contributive to ALD. Our labs have been studying the relationship between CYP2E1 and ALD for many years. Recently, we found that human CYP2A6 and its mouse analog CYP2A5 are also induced by alcohol. In mice, the alcohol induction of CYP2A5 is CYP2E1-dependent. Unlike CYP2E1, CYP2A5 protects against the development of ALD. The relationship of CYP2E1, CYP2A5, and ALD is a major focus of this review.

Mucositis is a side effect associated with the use of chemotherapy, and has a significant impact on the quality of life. Mucositis, by definition, refers to the inflammation of the mucosa and occurs throughout the alimentary tract from the mouth to anus. Nuclear Factor kappa B (NFΚB) encompasses a family of transcription factors, which upregulate pro-inflammatory cytokines. These are recognized as key targets in developing therapeutic interventions for chemotherapy-induced mucositis, and cyclooxygenase (COX)-2 inhibition may also be beneficial in reducing the severity and duration. This review focuses on the pathobiology of chemotherapy-induced oral and gastrointestinal mucositis and recent research examining the role of agents with anti-inflammatory activity in treatment and prevention of the condition. We consider agents in clinical use as well as some others under current investigation including plant-derived and other natural medicines.

Skin is a protective organ and the largest of the human body. Due to its pivotal role in aesthetic appearance, skin health has a significant impact on quality of life. Chronic inflammation of the skin often marks the beginning of various skin diseases. Immune-mediated responses serve to protect the body from external insults and require succinct control, and can lead to ongoing cellular damage and various skin conditions if left unchecked. Studies have shown that phytochemicals can alter processes involved in skin inflammation and alleviate the effects of aging, cancer, atopic dermatitis, psoriasis, and vitiligo. Direct molecular targets of some phytochemicals have been identified and their precise mechanisms of action investigated. In this review, we summarize recent findings on the effects of phytochemicals on skin inflammation and the mechanisms of action involved.

Inflammation is one of the most important body responses provided by the immune system since it ensures survival when tissues are affected by injuries or infections. The inflammatory response is an important process for maintenance of normal tissue homeostasis. In contrast to acute inflammation, chronic inflammation does not have a useful impact. Prevention and suppression of inflammation are necessary to reduce patient suffering and to preserve the integrity of multiple organs. Unfortunately, commercial available anti-inflammatory drugs are not free from side effects. Hence, there is an urgent need for introducing potent, nontoxic or less toxic antiinflammatory drugs. Recently, substantial progress has been made in the understanding of inflammatory mechanisms which may open new avenues for the preparation of novel anti-inflammatory drugs. Medicinal plants are also promising sources for preparation of such novel drugs. Taking into consideration the anti-inflammatory activities of a large group of medicinal plants, this article, in addition to describing recent advances in progress in understanding the molecular basis of inflammation, presents the most important medicinal plants with antiinflammatory activity.

Melatonin is an indolamine synthesized and secreted by the pineal gland along with other extrapineal sources including immune system cells, the brain, skin and the gastrointestinal tract. Growing interest in this compound as a potential therapeutic agent in several diseases stems from its pleiotropic effects. Thus, melatonin plays a key role in various physiological activities that include regulation of circadian rhythms, immune responses, the oxidative process, apoptosis or mitochondrial homeostasis. Most of these processes are altered during inflammatory pathologies, among which neurodegenerative and bowel diseases stand out. Therapeutic assays with melatonin indicate that it has a beneficial therapeutic value in the treatment of several inflammatory diseases, such as Alzheimer, Amiotrophic Lateral, Multiple Sclerosis and Huntigton´s disease as well as ulcerative colitis. However, contradictory effects have been demonstrated in Parkinson´s and Chron´s diseases, which, in some cases, the reported effects were beneficial while in others the pathology was exacerbated. These various results may be related to several factors. In the first place, it should be taken into account that at the beginning of the inflammation phase there is a production of reactive oxygen species (ROS) that should not be blocked by exclusively antioxidant molecules, since, on the one hand, it would be interfering with the action of neutrophils and macrophages and, on the other, with the apoptotic signals activated by ROS. It is also important to keep in mind that the end result of an anti-inflammatory molecule will depend on the degree of inflammation or whether or not it has been resolved and has therefore become chronic. In this review we present the use of melatonin in the control of inflammation underlying the above mentioned diseases. These actions are mediated through their receptors but also with their direct antioxidant action and melatonin's ability to break the vicious cycle of ROSinflammation. This review is aimed at evaluating the effect of melatonin on activity of the inflammatory process and at its immunomodulator effects.

Neurodegenerative diseases, like Alzheimer´s and Parkinson´s disease, are a group of disorders that have in common their increasingly high prevalence along with the shortage of effective treatments. In addition, the scientific community faces the challenge of getting the drugs used in these treatments to cross the blood-brain barrier (BBB) and reach the brain in sufficient concentration to be able to exert its effect. Hence, researchers across multiple disciplines are working together in order to improve the ability of therapeutics to penetrate the BBB. In this sense, the use of nanomedicine, nanoscale structures for drug delivery, exhibits a really high therapeutic potential in the field of neurodegenerative diseases therapy. Since there is new evidence that neuroinflammation produced by reactive microglia contributes to the activation and pathogenesis of neurological disorders, many investigations focus on the identification of new targets whose inhibition can reduce, totally or partially, microglial activation. This review analyzes a wide variety of compounds as possible candidates to achieve this target, from compounds with a natural origin to anti-diabetics, antidepressants, antibiotics and hormones. We also discuss the different strategies to enhance the capacity of these compounds to cross the BBB. Although this review focuses on PLGA nanoparticles as one of the most versatile drug delivery nanosystems, we also describe other strategies, such as direct intranasal administration (nose-tobrain), novel viral vectors and novel implanted catheters.

Inflammation has been very evident in infectious diseases, but in recent times research has increasingly shown that a range of non-infectious diseases may present with inflammatory conditions. This fact becomes important as new anti-inflammatory drugs emerge with different targets for treatment of diseases. Virtual screening (VS) involves applying computational methods to discover new ligands for biological structures from the formation of large libraries composed of a large number of compounds. This review aims to report several studies employing a variety of VS: ligand-based and structure-based VS are being used more frequently in combination to decrease the probability of choosing false positive candidates. There are also studies that use only one approach. Docking is widely employed as structure-based VS methodology, however pharmacophore models based on the structure are becoming more prevalent. Molecular dynamics simulations, despite their computational cost, are still utilized to validate docking scores and analyze the stability of the complex ligand-structure. It is important to note that several studies employed several drug-like rules to screen structures, as well, decoys and PAINS to validate the models. Natural product databases, despite the lower number of the compounds compared to other databases that are available, are commonly referred to as a source of drug-like molecules. There is a literal explosion of software being released for a variety of purposes and several of them are free tools and/or web tools. Overall, VS studies are nowadays a normal part of medicinal chemistry to determine novel potential inhibitors for targets of inflammatory diseases.