Brevicompanine E reduces lipopolysaccharide-induced production of proinflammatory cytokines and enzymes in microglia by inhibiting activation of activator protein-1 and nuclear factor-kappaB

Neurological disorders of COVID-19: insights to applications of natural products from plants and microorganisms

In addition to the typical respiratory manifestations, various disorders including involvement of the nerve system have been detected in COVID-19 ranging from 22 to 36%. Although growing records are focusing on neurological aspects of COVID-19, the pathophysiological mechanisms and related therapeutic methods remain obscure. Considering the increased concerns of SARS-CoV-2 potential for more serious neuroinvasion conditions, the present review attempts to focus on the neuroprotective effects of natural compounds as the principle source of therapeutics inhibiting multiple steps of the SARS-CoV-2 infection cycle. The great majority of the natural products with anti-SARS-CoV-2 activity mainly inhibit the attachment, entry and gene expression rather than the replication, assembly, or release. Although microbial-derived natural products comprise 38.5% of the known natural products with neuroprotective effects following viral infection, the neuroprotective potential of the majority of microorganisms is still undiscovered. Among natural products, chrysin, huperzine A, ginsenoside Rg1, pterostilbene, and terrein have shown potent in vitro neuroprotective activity and can be promising for new or repurpose drugs for neurological complications of SARS-CoV-2.

Marine-Derived Compounds for the Potential Treatment of Glucocorticoid Resistance in Severe Asthma

One of the challenges to the management of severe asthma is the poor therapeutic response to treatment with glucocorticosteroids. Compounds derived from marine sources have received increasing interest in recent years due to their prominent biologically active properties for biomedical applications, as well as their sustainability and safety for drug development. Based on the pathobiological features associated with glucocorticoid resistance in severe asthma, many studies have already described many glucocorticoid resistance mechanisms as potential therapeutic targets. On the other hand, in the last decade, many studies described the potentially anti-inflammatory effects of marine-derived biologically active compounds. Analyzing the underlying anti-inflammatory mechanisms of action for these marine-derived biologically active compounds, we observed some of the targeted pathogenic molecular mechanisms similar to those described in glucocorticoid (GC) resistant asthma. This article gathers the marine-derived compounds targeting pathogenic molecular mechanism involved in GC resistant asthma and provides a basis for the development of effective marine-derived drugs.

Oceans as a Source of Immunotherapy

Marine flora is taxonomically diverse, biologically active, and chemically unique. It is an excellent resource, which offers great opportunities for the discovery of new biopharmaceuticals such as immunomodulators and drugs targeting cancerous, inflammatory, microbial, and fungal diseases. The ability of some marine molecules to mediate specific inhibitory activities has been demonstrated in a range of cellular processes, including apoptosis, angiogenesis, and cell migration and adhesion. Immunomodulators have been shown to have significant therapeutic effects on immune-mediated diseases, but the search for safe and effective immunotherapies for other diseases such as sinusitis, atopic dermatitis, rheumatoid arthritis, asthma and allergies is ongoing. This review focuses on the marine-originated bioactive molecules with immunomodulatory potential, with a particular focus on the molecular mechanisms of specific agents with respect to their targets. It also addresses the commercial utilization of these compounds for possible drug improvement using metabolic engineering and genomics.

Structural Diversity and Biological Activities of the Cyclodipeptides from Fungi

Cyclodipeptides, called 2,5-diketopiperazines (2,5-DKPs), are obtained by the condensation of two amino acids. Fungi have been considered to be a rich source of novel and bioactive cyclodipeptides. This review highlights the occurrence, structures and biological activities of the fungal cyclodipeptides with the literature covered up to July 2017. A total of 635 fungal cyclodipeptides belonging to the groups of tryptophan-proline, tryptophan-tryptophan, tryptophan-Xaa, proline-Xaa, non-tryptophan-non-proline, and thio-analogs have been discussed and reviewed. They were mainly isolated from the genera of Aspergillus and Penicillium. More and more cyclodipeptides have been isolated from marine-derived and plant endophytic fungi. Some of them were screened to have cytotoxic, phytotoxic, antimicrobial, insecticidal, vasodilator, radical scavenging, antioxidant, brine shrimp lethal, antiviral, nematicidal, antituberculosis, and enzyme-inhibitory activities to show their potential applications in agriculture, medicinal, and food industry.

Precise manipulation of biophysical particle parameters enables control of proinflammatory cytokine production in presence of TLR 3 and 4 ligands

The biophysical parameters governing nanoparticle (NP)-cell interactions significantly affect biological responses, particularly in the application of NP-based immunotherapeutics. Modulation of the surface biophysical character of NPs can be achieved via introduction of amino acids, which offer the ability to fine tune a range of biophysical parameters of interest. We employed this approach using monodisperse silica NPs coated with numerous poly(amino acid)s (PAAs). The NPs were incubated with dendritic cells (DCs) in conjunction with TLR ligands and production of IL-1β from DCs and IFNγ from T cells primed by these DCs were measured. These key cytokines can prognosticate the efficacy of the NP platform as a potential vaccine or active cellular immunotherapy carrier. IL-1β production showed a correlation with both NP size and degree of hydrophobicity. High IFNγ secretion from T cells was shown to be correlated with both the hydrophobicity and charge of the NPs used to activate the DCs. Other cytokines were also screened in order to compare the immune responses. The results of this study highlight the importance of nanoparticle biophysical parameters and the selection of TLR ligands to the rational design of nanoparticle-based vaccines and immunotherapies.

STATEMENT OF SIGNIFICANCE

The manuscript describes a systematic investigation into the effects of biophysical parameters of nanoparticles (NPs) on immune cells. Modulation of the biophysical character of the NP surface can be achieved by introduction of amino acids on monodisperse silica NPs, introducing a range of tunable biophysical parameters of interest, i.e. distinct sizes, different surface charges and varying degrees of surface hydrophobicity. We examine internalization of the NP in dendritic cells (DCs) and measure a myriad of cytokines, including IL-1β and IFNγ, which prognosticate the efficacy of the NPs as a potential vaccine (IL-1β metric) or active cellular immunotherapy carrier (IFNγ metric). Two different TLR ligands (a viral TLR3 ligand and a bacterial TLR4 ligand) were used along with the PAA NPs to compare their costimulatory immunogenicity. We strongly believe that this study will provide crucial information to many readers of Acta Biomaterialia and further drive the use of nanoparticle platforms in modulating immune responses.

Aqueous extract from the Withania somnifera leaves as a potential anti-neuroinflammatory agent: a mechanistic study

Background

Microglial-mediated neuroinflammation is a key factor underlying the pathogenesis of various neurodegenerative diseases and also an important target for the development of the neuroinflammation-targeted therapeutics. Conventionally, the nonsteroidal anti-inflammatory drugs (NSAIDs) are prescribed, but they are associated with long-term potential risks. Natural products are the cornerstone of modern therapeutics, and Ashwagandha is one such plant which is well known for its immunomodulatory properties in Ayurveda.

Methods

The current study was aimed to investigate the anti-neuroinflammatory potential of Ashwagandha (Withania somnifera) leaf water extract (ASH-WEX) and one of its active chloroform fraction (fraction IV (FIV)) using β-amyloid and lipopolysaccharide (LPS)-stimulated primary microglial cells and BV-2 microglial cell line. Iba-1 and α-tubulin immunocytochemistry was done to study the LPS- and β-amyloid-induced morphological changes in microglial cells. Inflammatory molecules (NFkB, AP1), oxidative stress proteins (HSP 70, mortalin), apoptotic markers (Bcl-xl, PARP), cell cycle regulatory proteins (PCNA, Cyclin D1), and MHC II expression were analyzed by Western blotting. Mitotracker and CellRox Staining, Sandwich ELISA, and Gelatin Zymography were done to investigate ROS, pro-inflammatory cytokines, and matrix metalloproteinase production, respectively. Ashwagandha effect on microglial proliferation, migration, and its apoptosis-inducing potential was studied by cell cycle analysis, migration assay, and Annexin-V FITC assay, respectively.

Results

ASH-WEX and FIV pretreatment was seen to suppress the proliferation of activated microglia by causing cell cycle arrest at Go/G1 and G2/M phase along with decrease in cell cycle regulatory protein expression such as PCNA and Cyclin D1. Inhibition of microglial activation was revealed by their morphology and downregulated expression of microglial activation markers like MHC II and Iba-1. Both the extracts attenuated the TNF-α, IL-1β, IL-6, RNS, and ROS production via downregulating the expression of inflammatory proteins like NFkB and AP1. ASH-WEX and FIV also restricted the migration of activated microglia by downregulating metalloproteinase expression. Controlled proliferation rate was also accompanied by apoptosis of activated microglia. ASH-WEX and FIV were screened and found to possess Withaferin A and Withanone as active phytochemicals.

Conclusions

The current data suggests that ASH-WEX and FIV inhibit microglial activation and migration and may prove to be a potential therapeutic candidate for the suppression of neuroinflammation in the treatment of neurodegenerative diseases.

Bioactive Compounds Produced by Strains of Penicillium and Talaromyces of Marine Origin

In recent years, the search for novel natural compounds with bioactive properties has received a remarkable boost in view of their possible pharmaceutical exploitation. In this respect the sea is entitled to hold a prominent place, considering the potential of the manifold animals and plants interacting in this ecological context, which becomes even greater when their associated microbes are considered for bioprospecting. This is the case particularly of fungi, which have only recently started to be considered for their fundamental contribution to the biosynthetic potential of other more valued marine organisms. Also in this regard, strains of species which were previously considered typical terrestrial fungi, such as Penicillium and Talaromyces, disclose foreground relevance. This paper offers an overview of data published over the past 25 years concerning the production and biological activities of secondary metabolites of marine strains belonging to these genera, and their relevance as prospective drugs.

TDP-43 activates microglia through NF-κB and NLRP3 inflammasome

Transactive response DNA-binding protein-43 (TDP-43) is a multifunctional nucleic acid binding protein present in ubiquitinated inclusions in tissues of patients with amyotrophic lateral sclerosis (ALS) and fronto-temporal lobar degeneration (FTLD). The ALS-associated mutations in the glycine-rich C-terminal domain of TDP-43 established a causal link between TDP-43 and disease, and conferred both loss- and gain-of-function properties in neurons. Since it has not been established whether these intra-neuronal changes are sufficient to cause ALS or whether non-cell autonomous neuronal-glial signaling could be involved, we investigated the extracellular effects of TDP-43 proteins on microglial activation and motoneuron toxicity. Wild-type, truncated 25kD C-terminal fragments, or mutant forms of TDP-43 all activated microglia and upregulated NOX2, TNF-α, and IL-1β, with WT forms being significantly less effective in activating microglia. This response to TDP-43 was mediated by its interaction with the microglial surface CD14 receptor and subsequent stimulation of the NF-κB and AP-1 pathways, as well as the intracellular inflammasome. At the cell surface, CD14 blocking antibodies suppressed microglial NF-κB activation and proinflammatory cytokine production mediated by TDP-43. Intracellularly, the NLRP3 inflammasome was induced and functional caspase-1 was produced augmenting the release of mature IL-1β. Further, TDP-43-mediated activation of microglia caused a proinflammatory cascade that was toxic to motoneurons. In the absence of microglia, TDP-43 was not toxic to motoneurons. The ability of TDP-43 to promote CD14-mediated activation of microglial NF-κB and AP-1 pathways, as well as the NLRP3 inflammasome, suggests the involvement of a non-cell autonomous proinflammatory signaling that enhances motoneuron injury, and may offer novel therapeutic targets in ALS.

Preventive effect of phytoglycoprotein (27 kDa) on inflammatory factors at liver injury in cadmium chloride-exposed ICR mice

Cadmium is one of the inflammation-related xenobiotics and has been regarded as a potent carcinogen. Gardenia jasminoides Ellis (GJE) has been used to cure inflammation in Korean folk medicine for a long time. The purpose of present study is the inhibitory effect of glycoprotein isolated from GJE (27 kDa) on inflammation mechanism in cadmium chloride-exposed ICR mice. We evaluated the activities of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and thiobarbituric acid-reactive substances (TBARS), activities of anti-oxidative enzymes [superoxide dismutase (SOD) and gluthathione peroxidase (GPx)], activities of c-Jun N-terminal protein kinase (JNK), heat shock protein 27 (Hsp27), activator protein (AP)-1, nuclear factor (NF)-κB and expression of inflammation-related mediators including tumor necrosis factor (TNF)-α and interleukin (IL)-6 in cadmium chloride-exposed ICR mice using immunoblot analysis, EMSA and RT-PCR. It notes that mice plasma was used to measure ALT, LDH, and TBARS after treatment with cadmium chloride alone or cadmium chloride under the pretreatment with GJE glycoprotein. Liver tissues were used to assess activities of anti-oxidant enzymes, SAPK/JNK, Hsp27, AP-1, NF-κB, TNF-α, and IL-6 in this study. The results obtained from this study revealed that GJE glycoprotein (10 mg/kg) decreased the levels of LDH, ALT and TBARS, whereas increased the activity of hepatic anti-oxidant enzymes (SOD and GPx) in cadmium chloride-exposed ICR mice. Moreover, it decreased the activity of JNK/AP-1, NF-κB, Hsp27, and pro-inflammatory cytokines (TNF-α and IL-6). Taken together, the results in this study suggest that GJE glycoprotein inhibits the expression of inflammation-related cytokines (TNF-α and IL-6) in cadmium chloride-exposed ICR mice.

Lack of alpha-synuclein modulates microglial phenotype in vitro

Alpha (α)-synuclein neuronal effects are continually being defined although its role in regulating glial phenotypes remains unclear. An ability to regulate microglial activation was investigated using primary cultures from wild type and α-synuclein deficient mice (Snca-/-). Snca-/- microglia demonstrated increased secretion of the cytokine tumor necrosis factor-alpha (TNF-α), impaired phagocytic ability, elevated prostaglandin levels, and increased protein levels of key enzymes in lipid-mediated signaling events, cytosolic phospholipase (cPLA(2)), cyclooxygenase-2 (Cox-2) and phospholipase D2 (PLD2) when compared to wild type cells. Increased cytokine secretion and cPLA(2) and Cox-2 levels in Snca-/- microglia were partially attenuated by inhibiting PLD-dependent signaling with n-butanol treatment.