Current Molecular Medicine - Volume 20, Issue 8, 2020

Malaria is one of the three most deadly infectious diseases in the world and seriously endangers human health and life. To reduce the public health burden of this disease, scientists have focused on the discovery and development of effective antimalarial drugs, from quinine and chloroquine to antifolates and artemisinin and its derivatives, which all play a profound role in the treatment of malaria. However, drugresistant strains of Plasmodium falciparum have emerged due to frequent use of antimalarials and have become increasingly resistant to existing antimalarial drugs, causing disastrous consequences in the world. In particular, artemisinin resistance is of greatest concern which was reported in 2008. Resistance to artenisinins has been a major obstacle for malaria control, and current efforts to curb artemisinin resistance have not been successful. Based on the current situation, it is urgent to develop more effective new antimalarials with distinct targets from conventional antimalarials in the world, which could facilitate to minimize the phenomenon of drug resistance. This review aims to summarize different kinds of antimalarial therapeutic efficacy, mechanisms of action and resistance, and proposes new solutions aiming towards further improvement of malaria elimination.

The interest in biological peptides from Arthrospira sp. (syn Spirulina) is increasing due to its Generally Recognised as Safe “GRAS” status, the high concentration of proteins and the history of its use as a supplement and nutraceutical agent. Arthrospira peptides can be generated by the controlled hydrolysis of proteins, using proteases, followed by fractionation. The peptides obtained have a range of therapeutic effects. Amongst these bioactive peptides, three classes are of major importance: the antihypertensive (AHP), antimicrobial (AMP) and anticancer (ACP) peptides. AHPs have the ability to work as inhibitors of angiotensin-converting enzyme (ACE), and help to control several diseases such as hypertension, obesity, and cardiovascular issues, AMPs play a crucial role in the immune response, inhibiting the development of pathogens such as bacteria, fungi, viruses and others, while ACPs can aid in tumour control by the induction of apoptosis or necrosis, or the inhibition of angiogenesis. Thus, bioactive peptides are of great significance to the pharmaceutical industry. However, they can show secondary effects. This paper reviews the inhibition mechanism of antimicrobial, hypertensive and anticancer peptides from Arthrospira sp., and the possible structures of the peptides according to the type of activity and its intensity. In addition, this paper describes the purification methods of absorption mechanisms, and reviews databases for designing peptides.

Tuberculosis (TB) is the foremost cause of mortality from single infectious agent Mycobacterium tuberculosis (MTB). Current therapeutic regimes suffer from several problems, including side effects, costs and emergence of multidrug resistance (MDR). Moreover, conventional diagnostic methods are either too slow, or lack accurate and robust biomarkers. Under such circumstances, identification of rapid metabolite based biomarkers as novel drug targets could be a potential approach to circumvent MDR. In the era of “OMIC” sciences, lipidomics has gained significant attention to unravel the complexity of lipid-loaded Mycobacterium species. Lipidomics is a subbranch of metabolomics with extreme atomic diversity between the metabolites. There is no single principle on which the metabolite diversity can be defined, unlike other biomolecules viz. nucleic acid, proteins or carbohydrates. MTB encodes 10% of the genome for lipid metabolism and lipids account for 60% of its dry weight. Mycobacterium harbor a wide spectra of lipid repertoire ranging from highly apolar to highly polar lipids, adding complexity to their identification and analysis. Compared to targeted approaches, untargeted or global lipidomics of MTB is still more challenging. This review describes recent advances in lipidomics technology with regard to chromatography, detection methods and assessment on the existing mass spectrometry-based lipidomics tools to study the untargeted or global MTB lipidomics. It also identifies the limitations associated with present technologies as well as explores solutions to practical challenges concurrent with the establishment of MTB lipidome. Together we endorse that the emerging tools of lipidomics have provided a broader vision to comprehend the role of lipid molecules in MTB pathogenesis and the need for further improvements.

Purpose: A small molecular compound, aminooxy-acetic acid (AOA), has been shown to modulate experimental autoimmune encephalomyelitis (EAE). The current study was designed to investigate whether AOA has a similar effect on the development of experimental autoimmune uveitis (EAU) and to further explore underlying mechanisms of this drug. Methods: EAU was induced in C57BL/6J mice by immunization with interphotoreceptor retinoid-binding protein peptide 651-670 (IRBP 651-670). AOA (500μg or 750μg) or vehicle was administered by intraperitoneal injection from day 10 to 14 after EAU induction. The severity was assessed by clinical and histological scores. The integrity of the blood retinal barrier was detected with Evans Blue. Frequencies of splenic Th1, Th17 and Foxp3+ Treg cells were examined by flow cytometry. The production of cytokines was tested by ELISA. The mRNA expression of IL-17, IFN-γ and IL-10 was detected by RT-PCR. The expression of p-Stat1 and NF-ΚB was detected by Western Blotting. Results: AOA was found to markedly inhibit the severity of EAU, as determined by clinical and histopathological examinations. AOA can relieve the leakage of blood retinal barrier (BRB). Functional studies found a decreased frequency of Th1 and Th17 cells and an increased frequency of Treg cells in EAU mice as compared with controls. Further studies showed that AOA not only downregulated the production of the proinflammatory cytokines including IFN-γ and IL-17 but also upregulated the expression of an anti-inflammatory cytokine such as IL-10, which might be caused by inhibiting the expressions of p-Stat1 and NF-ΚB. Conclusion: This study shows that AOA inhibits the severity and development of EAU by modulating the balance between regulatory and pathogenic lymphocyte subsets.

Background: Recent studies have demonstrated that endometrial DNA methylation is essential for embryo implantation during early pregnancy. Dnmt3a is one of the key enzymes for DNA methylation and could be expressed in the endometrium regularly at this stage. Objective and Methods: In this study, we conditionally ablated uterine Dnmt3a using progesterone receptor-cre (Pgr^cre/+) to define the physiological roles of Dnmt3a in female reproduction. Results: We found that ovarian function was not apparently altered and the number of embryo implantation sites in Dnmt^loxP/loxP Pgr^cre/+ (cKO) was not significantly varied during early pregnancy. Western blotting and immunohistochemistry results showed no difference in expression or location of the estrogen receptor α (ERα) and mucin 1 (Muc1), the marker of uterine receptivity. Although the expression of decidual markers, matrix metalloproteinase-2 (Mmp2), matrix metalloproteinase-9(Mmp9), and bone morphogenetic protein-2 (Bmp2), was slightly decreased in Dnmt3a cKO females, the gross morphology of mice uteri during decidualization was not significantly influenced. In the artificial induction of the decidualization model, there was also no remarkable difference in visually observed morphology or uterine weight in Dnmt3a cKO. Lastly, a continuous breeding study showed that the fertility of Dnmt3a cKO female mice was not strikingly altered. Conclusion: Overall, these results demonstrated that although some decidual markers are expressed abnormally, conditional knockout of Dnmt3a in the uterus did not significantly affect the endometrial function during embryo implantation; the embryo could implant into the endometrium normally.

Backgrounds and Objective: Inflammation is implicated in the pathogenesis of many diseases. Inflammatory cytokines with painful conditions are well known as biomarkers in human muscle pain, and they are produced by macrophages. Metaxalone is used as a skeletal muscle relaxant, but the mechanism by which metaxalone acts is unknown. This study was undertaken to investigate whether or not metaxalone exhibits an inhibitory effect on the activity of inflammatory macrophages in vitro. Methods: Mouse macrophage RAW264.7 cells were cultured in Dulbecco’s Modification of Eagle’s Medium containing 10% fetal bovine serum in the presence of metaxalone. Cell growth was assayed by counting the number of cells attached to culture dishes. Inflammatory cytokines released into the culture medium were analyzed with the ELISA kit. Results: Metaxalone (1-100 μM) was found to decrease the number of macrophages by inhibiting the proliferation and stimulating the death of RAW264.7 cells in vitro. The combination of metaxalone (0.1 or 1 μM) and β-caryophyllene (10 or 50 μM), which alone did not have a significant effect on the cell number, caused potential effects on the growth and death of RAW264.7 cells. Mechanistically, molecular levels of mitogenactivated protein kinase were decreased by treatment with metaxalone or β- caryophyllene, and each effect was enhanced by their combination. Furthermore, levels of caspase-3 were increased by metaxalone or β-caryophyllene and enhanced by their combination. Notably, productions of inflammatory cytokines, including tumor necrosis factor-α, interleukin-6 or prostaglandin E2, which were enhanced by lipopolysaccharide (LPS), were repressed by culturing with metaxalone. Levels of cyclooxygenase (COX)-1, COX-2 and nuclear factor kappa B, which were increased by LPS treatment, were reduced by metaxalone. Conclusion: Metaxalone was found to suppress the activity of inflammatory macrophages in vitro.

Aims: The aim of this study was to investigate MacroH2A.1 immunoexpression in tissues of sheep exposed to FE. Background: The correlation between asbestiform fibers, lung cancer, pleural mesothelioma, and other lung diseases is already well established as the pathophisiological pathophysiological respiratory mechanisms involved by inhalation of Fluoro-edenite (FE). The latter is represented by cell proliferation and inducing the release of growth factors, cytokines, and reactive oxygen and nitrite species, with DNA damage that causes chronic inflammation and carcinogenesis. MacroH2A.1, and histone variant, seems to play a role in sensing the metabolic state of the cell and linking it with chromatin. Physiologically, MacroH2A.1 is expressed at low levels in stem cells and it became upregulated during differentiation, preventing reprogramming of induced pluripotent stem cells and after nuclear transfer. In particular, MacroH2A.1 has been shown to explicate a potent antitumor mechanism in vivo as it results upregulated in senescent cells determining a permanent growth-arrest. Objective: Evaluate the possible role of the histone variant in the organism in response to deep insight understanding the mechanisms of toxicity and the cellular response to FE. Methods: Lung and lymph nodes of exposed sheep were selected. Samples were processed for histological and immunihistochemical immunohistochemical evaluations. Densitometric, morphometric, and statistical analysis analyses were conducted. Results: Tissue sections of FE exposed sheep demonstrated overexpression of MacroH2A.1 vs unexposed samples. The data suggest an involvement of these this molecule in the cellular response triggered by FE directed exposure. Conclusion: In this contest, MacroH2A.1 overexpression supports its function as an epigenetic stabilizer that helps to establish and maintain differentiated states.

Background: Persistent hyperlactatemia is associated with greater mortality in shock. Liver is the main site of lactate metabolism. Method: In the first part, freshly isolated hepatocytes were incubated in 10% fetal bovine serum William's E medium supplemented with 10 mM lactate. Cells were then exposed to 100 μM ursodeoxycholic acid (UDCA), with no addition (control) for 2, 4, 6, 8 h. In the second part, hepatocytes were treated with Silencer select siRNA targeting FXR or scramble siRNA. The siRNA treatment was repeated twenty four hours later, and the cells were used in the experiments twenty-four hours after the second treatment. Then hepatocytes were incubated in 10% fetal bovine serum William's E medium supplemented with 10 mM lactate. Cells were then exposed to 100 μM UDCA for 2, 4, 6, 8 h. Lactate concentration was determined by ABL80 automatic blood gas analyzer. Results: UDCA increased ability of hepatocytes to remove lactate. After the knockdown of FXR, effects caused by UDCA were weakened. Conclusion: These results demonstrate that UDCA promotes lactate metabolism in mouse hepatocytes through CA-FXR pathway.