Endothelial dysfunction in Sickle Cell Disease: Strategies for the treatment.

Sickle Cell Anemia (SCA), is an inherited hemoglobinopathy characterized by the presence of an abnormal hemoglobin (HbS), being the most prevalent sickle cell disease (SCD). SCA is characterized by vascular endothelial dysfunction, which contributes significantly to various clinical conditions, including but not limited to pulmonary hypertension, priapism, cutaneous leg ulceration, and stroke. The pathophysiology of endothelial dysfunction (ED) in SCA is a multifaceted process involving a chronic inflammatory and hypercoagulable state. Key factors include hemolysis-associated elements like reduced arginine and nitric oxide (NO) availability, elevated levels of vascular adhesion molecules, the uncoupling effect of NO synthase, heightened arginase activity, an environment characterized by oxidative stress with the production of reactive oxygen and nitrogen species, and occurrences of ischemia-reperfusion injury, along with apolipoprotein A-1 depletion. The urgency for novel interventions addressing ED is evident. Presently, there is a focus on investigating small molecules that disrupt the arginine-nitric oxide pathway, exhibiting anti-inflammatory and antioxidant properties while diminishing levels of cellular and vascular adhesion molecules. In this mini-review article, we delve into the progress made in strategies for treating ED in SCD with the aim of cultivating insights for drug design.

In silico drug design strategies for discovering novel tuberculosis therapeutics.

INTRODUCTION: Tuberculosis remains a significant concern in global public health due to its intricate biology and propensity for developing antibiotic resistance. Discovering new drugs is a protracted and expensive endeavor, often spanning over a decade and incurring costs in the billions. However, computer-aided drug design (CADD) has surfaced as a nimbler and more cost-effective alternative. CADD tools enable us to decipher the interactions between therapeutic targets and novel drugs, making them invaluable in the quest for new tuberculosis treatments. AREAS COVERED: In this review, the authors explore recent advancements in tuberculosis drug discovery enabled by in silico tools. The main objectives of this review article are to highlight emerging drug candidates identified through in silico methods and to provide an update on the therapeutic targets associated with Mycobacterium tuberculosis. EXPERT OPINION: These in silico methods have not only streamlined the drug discovery process but also opened up new horizons for finding novel drug candidates and repositioning existing ones. The continued advancements in these fields hold great promise for more efficient, ethical, and successful drug development in the future.

BacPROTACs targeting Clp protease: a promising strategy for anti-mycobacterial drug discovery.

Tuberculosis (TB) has claimed more lives over the course of two millennia than any other infectious disease worldwide. In 2021, the World Health Organization (WHO) estimated that 10.6 million people were diagnosed with TB, resulting in the deaths of 1.4 million HIV-negative individuals. The emergence of multidrug-resistant TB (MDR-TB), defined as resistance to at least rifampicin (RIF) and isoniazid (INH), and extensively drug-resistant TB (XDR-TB), poses the primary challenge to overcome in the coming years. We have recently conducted an extensive analysis of investments and research endeavours in the field, with the overarching objective of achieving the established milestone of TB eradication by the year 2030. Over the past several years, there has been notable progress in advancing a multitude of promising compounds, each possessing distinct mechanisms of action, into clinical phases of development. However, it is worth noting that strains of mycobacteria resistant to current antitubercular drugs have already emerged for some of these compounds The exploration of the innovative Proteolytic Target Chimeras (PROTACs) protein degradation approach has emerged as a viable avenue for the discovery of novel antimicrobials. While the ubiquitin system is exclusive to eukaryotic cells, certain bacteria use a similar degradation system that relies on the recognition of phosphorylated arginine residues (pArg) by the ClpC:ClpP (ClpCP) protease, thereby leading to protein degradation. In this opinion article, we have described and analized the advances in the use of PROTACs that leverage bacterial proteolytic machinery (BacPROTACs) to design new antitubercular agents. Scope Statement. The development of novel pharmaceuticals for tuberculosis treatment is deemed urgently necessary due to the emergence of resistant strains. In this context, the introduction of new technologies capable of alleviating the disease and attaining the objectives outlined by the World Health Organization is imperative. Among the innovative strategies, the degradation of proteins that are crucial for the survival of the bacillus holds promise for generating new medications, particularly those that are effective at treating latent (non-replicating) Mycobacterium tuberculosis. Within this perspective, we present the advancements and obstacles encountered in the exploration of new BacPROTAC compounds, with the intention of encouraging research and illuminating challenges associated with the implementation of BacPROTACs to address to the global tuberculosis crisis.

Vascular Effects of the Fetal Hemoglobin Inducer Agent 3-(1,3-Dioxoisoindolin-2-yl) Benzyl Nitrate.

Vascular endothelium is a protective layer of cells lining the lumen of blood vessels that plays important roles by releasing factors responsible for controlling the vascular tone, regulating the expression of pro-inflammatory cytokines, and expressing adhesion molecules involved in vascular hemostasis. Imbalance of vascular properties leads to endothelial dysfunction (ED) and cardiovascular damage. Some diseases, such as sickle cell anemia, are characterized by ED with reduction in the levels of nitric oxide (NO). Previously, we have shown that the fetal hemoglobin inducer agent 3-(1,3-dioxoisoindolin-2-yl) benzyl nitrate (Lapdesf-4c) could act as NO donor, inhibiting platelet aggregation and reducing the inflammation associated with SCA. However, the vascular effect of this compound was not yet studied. Herein, we evaluated the effects of Lapdesf-4c in vascular reactivity experiments using aortic rings from male Wistar rats (300 g/90 days). We have found that Lapdesf-4c induced vasodilation in the presence (E+) or absence of endothelium (E-) with an average of EMax values of 101.8 ± 3.33% and 111.8 ± 3.21%. The mechanism of action was studied using 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one (ODQ), L-NG-nitroarginine methyl ester (L-NAME), and hydroxocobalamin. The EMax values for those pathways were hydroxocobalamin (30.6 ± 2.21%), ODQ (4.75 ± 0.51%), and L-NAME (109 ± 3.65), suggesting that Lapdesf-4c exhibits NO-dependent mechanisms. Lapdesf-4c was able to prevent angiotensin-induced ED after incubation of aorta rings for 1 h. We found based on the concentration-effect curve using acetylcholine (ACh) that pEC50 values for the control, Ang II, and combination of (Ang II + Lapdesf-4c) were 6.73, 6.46, and 7.15, respectively. In conclusion, Lapdesf-4c has emerged as a new drug candidate that can promote vasodilation and act as a protective agent against ED, being useful to prevent vascular damage.

Optimization of Resveratrol Used as a Scaffold to Design Histone Deacetylase (HDAC-1 and HDAC-2) Inhibitors.

Histone deacetylases (HDAC) are epigenetic enzymes responsible for repressing gene expression through the deacetylation of histone lysine residues. Therefore, inhibition of HDACs has become an interesting approach for the treatment of several diseases, including cancer, hematology, neurodegenerative, immune diseases, bacterial infections, and more. Resveratrol (RVT) has pleiotropic effects, including pan-inhibition of HDAC isoforms; however, its ability to interfere with membranes requires additional optimization to eliminate nonspecific and off-target effects. Thus, to explore RVT as a scaffold, we designed a series of novel HDAC-1 and -2 inhibitors containing the 2-aminobenzamide subunit. Using molecular modeling, all compounds, except unsaturated compounds (4) and (7), exhibited a similar mode of interaction at the active sites of HDAC 1 and 2. The docking score values obtained from the study ranged from -12.780 to -10.967 Kcal/mol. All compounds were synthesized, with overall yields ranging from 33% to 67.3%. In an initial screening, compounds (4), (5), (7), and (20)-(26), showed enzymatic inhibitory effects ranging from 1 to 96% and 6 to 93% against HDAC-1 and HDAC-2, respectively. Compound (5), the most promising HDAC inhibitor in this series, was selected for IC50 assays, resulting in IC50 values of 0.44 µM and 0.37 µM against HDAC-1 and HDAC-2, respectively. In a panel of selectivity against HDACs 3-11, compound (5) presented selectivity towards Class I, mainly HDAC-1, 2, and 3. All compounds exhibited suitable physicochemical and ADMET properties as determined using in silico simulations. In conclusion, the optimization of the RVT structure allows the design of selective HDAC inhibitors, mainly targeting HDAC-1 and HDAC-2 isoforms.

The state of the art of fetal hemoglobin-inducing agents.

INTRODUCTION: Sickle cell anemia (SCA) is a hematological genetic disorder caused by a mutation in the gene of the ß-globin. Pharmacological treatments will continue to be an important approach, including the strategy to induce fetal hemoglobin (HbF). AREAS COVERED: Here, we analyzed the articles described in the literature regarding the drug discovery of HbF inducers. The main approaches for such strategy will be discussed, highlighting those most promising. EXPERT OPINION: The comprehension of the mechanisms involved in the ß-globin regulation is the main key to design new drugs to induce HbF. Among the strategies, gamma-globin regulation by epigenetic enzymes seems to be a promising approach to be pursued, although the comprehension of the selectivity role for those new drugs is crucial to reduce adverse effects. The low druggability of transcription factors and their vital role in embryonic human development are critical points that should be taken in account for drug design. The guanylate cyclase and the NO/cGMP signaling pathway seem to be promising not only for HbF induction, but also for the protective effects in the cardiovascular system. The association of drugs acting through different mechanisms to induce HbF seems to be promising for the discovery of new drugs.

Advances in Sickle Cell Disease Treatments.

Sickle Cell Disease (SCD) is an inherited disorder of red blood cells that is caused by a single mutation in the ß -globin gene. The disease, which afflicts millions of patients worldwide mainly in low income countries, is characterized by high morbidity, mortality and low life expectancy. The new pharmacological and non-pharmacological strategies for SCD is urgent in order to promote treatments able to reduce patient's suffering and improve their quality of life. Since the FDA approval of HU in 1998, there have been few advances in discovering new drugs; however, in the last three years voxelotor, crizanlizumab, and glutamine have been approved as new therapeutic alternatives. In addition, new promising compounds have been described to treat the main SCD symptoms. Herein, focusing on drug discovery, we discuss new strategies to treat SCD that have been carried out in the last ten years to discover new, safe, and effective treatments. Moreover, non-pharmacological approaches, including red blood cell exchange, gene therapy and hematopoietic stem cell transplantation will be presented.

Synthesis and evaluation of resveratrol derivatives as fetal hemoglobin inducers.

Resveratrol (RVT) derivatives (10a-i) were designed, synthesized, and evaluated for their potential as gamma-globin inducers in treating Sickle Cell Disease (SCD) symptoms. All compounds were able to release NO at different levels ranging from 0 to 26.3%, while RVT did not demonstrate this effect. In vivo, the antinociceptive effect was characterized using an acetic acid-induced abdominal contortion model. All compounds exhibited different levels of protection, ranging from 5.9 to 37.3%; the compound 10a was the most potent among the series. At concentrations between 3.13 and 12.5 µM, the derivative 10a resulted in a reduction of 41.1-64.3% in the TNF-α levels in the supernatants of macrophages that were previously LPS-stimulated. This inhibitory effect was higher than that of RVT used as the control. In addition, the compound 10a and RVT induced double the production of the gamma-globin chains (γG + Î³A), compared to the vehicle, using CD34+ cells. Compound 10a also did not induce membrane perturbation and it was not mutagenic in the in vivo assay. Thus, compound 10a emerged as a new prototype of the gamma-globin-inducer group with additional analgesic and anti-inflammatory activities and proving to be a useful alternative to treat SCD symptoms.

Histone Deacetylase Inhibitors as Therapeutic Interventions on Cervical Cancer Induced by Human Papillomavirus.

The role of epigenetic modifications on the carcinogenesis process has received a lot of attention in the last years. Among those, histone acetylation is a process regulated by histone deacetylases (HDAC) and histone acetyltransferases (HAT), and it plays an important role in epigenetic regulation, allowing the control of the gene expression. HDAC inhibitors (HDACi) induce cancer cell cycle arrest, differentiation, and cell death and reduce angiogenesis and other cellular events. Human papillomaviruses (HPVs) are small, non-enveloped double-stranded DNA viruses. They are major human carcinogens, being intricately linked to the development of cancer in 4.5% of the patients diagnosed with cancer worldwide. Long-term infection of high-risk (HR) HPV types, mainly HPV16 and HPV18, is one of the major risk factors responsible for promoting cervical cancer development. In vitro and in vivo assays have demonstrated that HDACi could be a promising therapy to HPV-related cervical cancer. Regardless of some controversial studies, the therapy with HDACi could target several cellular targets which HR-HPV oncoproteins could be able to deregulate. This review article describes the role of HDACi as a possible intervention in cervical cancer treatment induced by HPV, highlighting the main advances reached in the last years and providing insights for further investigations regarding those agents against cervical cancer.

Heterocyclic N-oxides - A Promising Class of Agents against Tuberculosis, Malaria and Neglected Tropical Diseases.

Heterocyclic N-oxides have emerged as promising agents against a number of diseases and disorders, especially infectious diseases. This review analyzes the emergence and development of this scaffold in the medicinal chemistry, focusing mainly on the discovery of new heterocyclic N-oxide compounds with potent activity against tuberculosis, malaria and neglected tropical diseases (i.e. leishmaniasis and Chagas disease). A number of heterocyclic N-oxides are described herein, nevertheless, the following chemical classes deserve to be highlighted due to a large number of reports in the literature about their promising pharmacological effects: furoxan, benzofuroxan, quinoxaline 1,4-di-N-oxide, indolone N-oxide and benzimidazole N-oxide. In order to describe those most promising compounds, we included in this review only those most biologically active heterocyclic Noxide published since 2000.

Epigenetic Regulatory Mechanisms Induced by Resveratrol.

Resveratrol (RVT) is one of the main natural compounds studied worldwide due to its potential therapeutic use in the treatment of many diseases, including cancer, diabetes, cardiovascular diseases, neurodegenerative diseases and metabolic disorders. Nevertheless, the mechanism of action of RVT in all of these conditions is not completely understood, as it can modify not only biochemical pathways but also epigenetic mechanisms. In this paper, we analyze the biological activities exhibited by RVT with a focus on the epigenetic mechanisms, especially those related to DNA methyltransferase (DNMT), histone deacetylase (HDAC) and lysine-specific demethylase-1 (LSD1).

Unraveling the Anticancer Effect of Curcumin and Resveratrol.

Resveratrol and curcumin are natural products with important therapeutic properties useful to treat several human diseases, including cancer. In the last years, the number of studies describing the effect of both polyphenols against cancer has increased; however, the mechanism of action in all of those cases is not completely comprehended. The unspecific effect and the ability to interfere in assays by both polyphenols make this challenge even more difficult. Herein, we analyzed the anticancer activity of resveratrol and curcumin reported in the literature in the last 11 years, in order to unravel the molecular mechanism of action of both compounds. Molecular targets and cellular pathways will be described. Furthermore, we also discussed the ability of these natural products act as chemopreventive and its use in association with other anticancer drugs.

Synthesis and Preliminary Evaluation of N-Oxide Derivatives for the Prevention of Atherothrombotic Events.

Thrombosis is the main outcome of many cardiovascular diseases. Current treatments to prevent thrombotic events involve the long-term use of antiplatelet drugs. However, this therapy has several limitations, thereby justifying the development of new drugs. A series of N-oxide derivatives (furoxan and benzofuroxan) were synthesized and characterized as potential antiplatelet/antithrombotic compounds. All compounds (3a,b, 4a,b, 8a,b, 9a,b, 13a,b and 14a,b) inhibited platelet aggregation induced by adenosine-5-diphosphate, collagen, and arachidonic acid. All compounds protected mice from pulmonary thromboembolism induced by a mixture of collagen and epinephrine; however, benzofuroxan derivatives (13a,b and 14a,b) were the most active compounds, reducing thromboembolic events by up to 80%. N-oxide derivative 14a did not induce genotoxicity in vivo. In conclusion, 14a has emerged as a new antiplatelet/antithrombotic prototype useful for the prevention of atherothrombotic events.