Design and Evaluation of a Novel Peptide-Drug Conjugate Covalently Targeting SARS-CoV-2 Papain-like Protease.

Coronavirus disease 2019 (COVID-19) pandemic, a global health threat, was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 papain-like cysteine protease (PLpro) was recognized as a promising drug target because of multiple functions in virus maturation and antiviral immune responses. Inhibitor GRL0617 occupied the interferon-stimulated gene 15 (ISG15) C-terminus-binding pocket and showed an effective antiviral inhibition. Here, we described a novel peptide-drug conjugate (PDC), in which GRL0617 was linked to a sulfonium-tethered peptide derived from PLpro-specific substrate LRGG. The EM-C and EC-M PDCs showed a promising in vitro IC50 of 7.40 ± 0.37 and 8.63 ± 0.55 µM, respectively. EC-M could covalently label PLpro active site C111 and display anti-ISGylation activities in cellular assays. The results represent the first attempt to design PDCs composed of stabilized peptide inhibitors and GRL0617 to inhibit PLpro. These novel PDCs provide promising opportunities for antiviral drug design.

Effects of rhizome of Atractylodes koreana (Nakai) Kitam on intestinal flora and metabolites in rats with rheumatoid arthritis.

ETHNOPHARMACOLOGICAL RELEVANCE: Atractylodis rhizoma in Chinese Pharmacopoeia are Atractylodes lancea (Thunb.) DC and Atractylodes chinensis (DC.) Koidz. Atractylodes koreana (Nakai) Kitam has not been included in Chinese Pharmacopoeia, however, in the 'dictionary of traditional Chinese medicine', Atractylodes koreana (Nakai) Kitam is often used as Atractylodis rhizoma in the north of China. According to 'Chinese traditional medicine resources', Atractylodes koreana (Nakai) Kitam has the function of drying dampness and strengthening the spleen, dispelling wind and eliminating dampness. AIM OF THIS STUDY: The study was to explore the effect and mechanism of Atractylodes koreana (Nakai) Kitam on rheumatoid arthritis(RA) through intestinal flora and its metabolites(short chain fatty acids). MATERIALS AND METHODS: 36 male SD rats were randomly divided into 6 groups. The Freund's complete adjuvant method was used to reproduce RA model. The contents of inflammatory factors in the plasma of rats were monitored by ELISA method. The pathological changes of synovium were observed. 16SrDNA high-throughput sequence method was used to study the composition and structure of intestinal microflora in each group of rats. Gas Chromatography and Mass Spectrum(GC-MS) method was used to determine the content of short chain fatty acids(SCFAs) in colon of rats of each group. RESULTS: After oral administration of Atractylodes koreana (Nakai) Kitam, the synovial infiltration and vascular proliferation in RA rats were alleviated, the level of TNF - α, IL-1, IL-1 ß, IL-2, IL-6, hs-CRP in the plasma of RA rats were declined. RA could cause the disturbance of intestinal flora and SCFAs, Atractylodes koreana (Nakai) Kitam could regulate 8 genera of intestinal flora and improve the disorder of SCFAs. CONCLUSIONS: Atractylodes koreana (Nakai) Kitam has a therapeutic effect on RA, the therapeutic mechanism may be related to down-regulating inflammatory factors and improving the imbalance of intestinal flora and SCFAs.

The antiinflammatory effects of Xuefu Zhuyu decoction on C3H/HeJ mice with alopecia areata.

BACKGROUND: As a traditional and typical prescription of prominently activating blood circulation to remove blood stasis, Xuefu Zhuyu decoction (XZD) consists of 15 kinds of herbal medicine. Clinical investigations have showed that XZD could significantly promote the new hair generation of alopecia areata (AA) patients characterized by Qi stagnation and blood stasis. PURPOSE: The purpose of this study was executed to determine whether the mechanisms by which XZD stimulated newborn hair were related to its anti-inflammatory effects. METHODS: Clinical AA individuals were recruited to confirm the efficies of XZD. High performance liquid chromatography (HPLC) analysis was performed to qualitatively and quantitatively determine the contents of 15 compounds in XZD. Schrodinger molecular docking and in vivo surface plasmon resonance (SPR) techniques were used to evaluate the potential binding properties of compounds to target proteins. C3H/HeJ mice were randomly assigned to groups control, AA, and the XZD administration (6.5, 13.0 and 26.0 g/kg/d). Except for mice in control group, all the mice in the other groups were treated with a 21-day chronic unpredictable mild stress (CUMS) induced AA. Hematoxylin-eosin (H&E) staining was performed to determine the degree of pathological damage to the skin. Enzyme-linked immunosorbent assay (ELISA) was performed to detect levels of interleukin-6 (IL-6), interleukin-1 beta (IL-1ß) and tumor necrosis factor alpha (TNF-α) and in serum and skin tissues. Western blot, immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were used to examine the expression levels of IL-6, IL-1ß, TNF-α and osteopontin proteins and genes in skin tissues. RESULTS: XZD could visibly promote hair regeneration of AA patients. The potential active ingredients in XZD prescription included at least amygdalin, hydroxysafflor yellow A, kaempferide, ferulic acid, catalpol, verbascoside, ß-ecdysone, platycodin D, paeoniflorin, naringin, neohesperidin, liquiritin, glycyrrhizic acid, saikosaponin A and saikosaponin D. The results of molecular docking and SPR analysis showed that verbascoside, liquiritin, kaempferide and amygdalin showed the best potential binding properties with IL-6, IL-1ß, TNF-α and osteopontin, respectively. Pathological evaluation showed that compared with the CUMS group, the administration of XZD significantly promoted hair regeneration, evidenced by increased number of skin hair follicles in C3H/HeJ AA mice. Compared with control group, ELISA data showed that the levels of IL-6, IL-1ß and TNF-α in serum and skin tissues of CUMS induced AA mice were significantly increased, while XZD administration dramatically restrained the contents of the three pro-inflammatory factors. Western blot, immunohistochemistry, and qRT-PCR results further demonstrated that XZD administration notably down-regulated the protein and gene expression levels of osteopontin, IL-6, IL-1ß and TNF-α in comparation with CUMS group. CONCLUSION: XZD could dramatically ameliorate CUMS-induced AA damage in the skin of C3H/HeJ mice, possibly by suppressing the levels of IL-6, IL-1ß, TNF-α and osteopontin.

A new bisepoxylignan dendranlignan A isolated from Chrysanthemum Flower inhibits the production of inflammatory mediators via the TLR4 pathway in LPS-induced H9c2 cardiomyocytes.

A new bisepoxylignan dendranlignan A (A1) and the known compound lantibeside D (D2) was isolated from Chrysanthemum Flower, the dried capitulum of Dendranthema morifolium (Ramat.) kitam. Their structures were determined on the basis of extensive spectroscopic methods, including 1D-NMR, 2D-NMR and MS data. Additionally, A1 and D2 were evaluated for their effects on the production of inflammatory mediators in H9c2 cardiomyocytes stimulated with lipopolysaccharide (LPS). Results demonstrated that A1 and D2 decreased LPS-induced production of inflammatory cytokines TNF-α, IL-2 and IFN-γ in H9c2 cells. Both compounds also decreased the nuclear localization of c-JUN, p-P65 and p-IRF3, but did not affect the level of TLR4. Molecular docking indicated that A1 and D2 occupied the ligand binding sites of TLR4-MD2. In the present study, we for the first time discovered a new bisepoxylignan compound A1, and found that this compound has a potential to inhibit inflammation by inhibiting TLR4 signaling.

Cytokine-Encapsulated Biodegradable Microspheres for Immune Therapy.

Therapeutic macromolecules such as proteins are conventionally administered via bolus injection, an approach that presents significant limitations. Sustained-release biodegradable nano/microsphere depots, on the other hand, represent a more physiological delivery tool for biologics. Here, we focus on an emerging novel application of this technology, i.e., cytokine-encapsulated biodegradable microspheres as immune therapeutics. The overall pre-clinical experience, recent advances and the clinical potential of such formulations are discussed.

Structure-based identification of potential novel inhibitors targeting FAM3B (PANDER) causing type 2 diabetes mellitus through virtual screening.

Type 2 diabetes mellitus is a metabolic disorder that requires potent therapeutic approaches. The FAM3B is a cytokine-like protein also referred to as PANcreatic-DERrived factor (PANDER) which mainly exists in pancreatic islets. In the process of identifying potential inhibitors with the aid of structure-based method PANDER protein is identified as a novel therapeutic target against type 2 diabetes mellitus as it involved in the development of type 2 diabetes by negatively regulating the pancreatic ß-cell function and insulin sensitivity in the liver. In the present study, the 3d model of target protein FAM3B was generated by homology modeling technique using the MODELLER9.9 program. The assessment of the structural stability of the 3d model was established by energy minimization technique. The structural quality was evaluated with standard validating protocols. Binding regions of the target protein has been determined by literature and SiteMap tool. In the current study of research, the FAM3B model was subjected to molecular screening with the Asinex-elite database of 14849 output molecules using the Glide virtual screening module in the Schrodinger suite. The final XP descriptor output of 14 molecules was analyzed and prioritized based on molecular interactions at the FAM3B active site. The docking score, binding free energies (Prime MM/GBSA) and bioavailability were undertaken into the consideration to identify lead inhibitors. The identified lead compounds were checked for ADME properties all falling within the permeable ranges. The analysis of results gave the insight to develop the novel therapeutic strategies against type 2 diabetes mellitus.

[Immunotoxins and immunocytokines]. / Immunotoxines et immunocytokines.

Cytokines and biological toxins represent two potent classes of biomolecules that have long been explored for their potential as therapeutics. Considerable side effects and poor pharmacokinetics frequently observed with both have limited their broad application. Recombinant protein engineering has allowed the construction of immunocytokines and immunotoxins that seek to exploit the advantageous properties of immunoglobulins to address these issues. Whole antibodies, antibody fragments, constant domains and derivatives have been fused genetically to a range of cytokines and toxins. This review considers the strategies that have been employed and the problems sought to be resolved in the clinical evaluation of this class of biotherapeutic.

TITLE: Immunotoxines et immunocytokines. ABSTRACT: Les cytokines et les toxines biologiques représentent deux classes de biomolécules qui ont longtemps été explorées pour leur potentiel thérapeutique. Des effets secondaires considérables et des mauvaises propriétés pharmacocinétiques sont fréquemment observés chez chacune d'elles, ce qui limite leur application. L'ingénierie des protéines recombinantes a permis la création d'immunocytokines et d'immunotoxines qui visent à utiliser les propriétés avantageuses des immunoglobulines, pour résoudre ces problèmes. Des anticorps entiers, des fragments d'anticorps, des domaines constants et des dérivés ont été génétiquement fusionnés à une gamme de cytokines et de toxines. Cette revue présente les stratégies déployées et les problèmes à résoudre au cours de l'évaluation clinique pour cette classe de biothérapeutiques.

Andalucin from Artemisia lannta suppresses the neuroinflammation via the promotion of Nrf2-mediated HO-1 levels by blocking the p65-p300 interaction in LPS-activated BV2 microglia.

BACKGROUND: Neuroinflammation plays an important role in many neurodegenerative conditions such as Alzheimer's disease (AD) and Parkinson disease (PD). Andalucin (ADL), a sesquiterpene lactone from Artemisia lannta, has been reported to exhibit NO inhibition in vitro. However, the effect of ADL on microglia-mediated neuroinflammation has not been investigated. PURPOSE: This study was designed to determine the anti-neuroinflammatory effect of ADL against LPS-activated BV2 microglial cells and to explore the underlying mechanisms. METHODS: The production of pro-inflammatory mediators and cytokines were measured by ELISA. The relevant mechanisms were analyzed by qRT-PCR, Luciferase assay, Western blot and Co-immunoprecipitation Assay. RESULTS: ADL inhibited the LPS-induced release of NO, PGE2, TNF-α, IL-6 and IL-1ß. In addition, ADL reduced the mRNA and protein levels of iNOS and COX-2. Mechanism studies found that ADL activated Nrf2/HO-1 signaling pathway and suppressed NF-κB signaling pathway. Further investigation showed that the stimulative effect of ADL on Nrf2 transcriptional activity and the inhibitory effect of ADL on RelA transcriptional activity were due to its regulation on p300-Nrf2/p65 interaction. CONCLUSION: ADL displayed anti-neuroinflammatory activity in LPS-activated BV2 cells. The mechanism concerns its regulatory effect on the crosstalk between Nrf2 and p65.

Virtual screening for inhibitors of the human TSLP:TSLPR interaction.

The pro-inflammatory cytokine thymic stromal lymphopoietin (TSLP) plays a pivotal role in the pathophysiology of various allergy disorders that are mediated by type 2 helper T cell (Th2) responses, such as asthma and atopic dermatitis. TSLP forms a ternary complex with the TSLP receptor (TSLPR) and the interleukin-7-receptor subunit alpha (IL-7Rα), thereby activating a signaling cascade that culminates in the release of pro-inflammatory mediators. In this study, we conducted an in silico characterization of the TSLP:TSLPR complex to investigate the drugability of this complex. Two commercially available fragment libraries were screened computationally for possible inhibitors and a selection of fragments was subsequently tested in vitro. The screening setup consisted of two orthogonal assays measuring TSLP binding to TSLPR: a BLI-based assay and a biochemical assay based on a TSLP:alkaline phosphatase fusion protein. Four fragments pertaining to diverse chemical classes were identified to reduce TSLP:TSLPR complex formation to less than 75% in millimolar concentrations. We have used unbiased molecular dynamics simulations to develop a Markov state model that characterized the binding pathway of the most interesting compound. This work provides a proof-of-principle for use of fragments in the inhibition of TSLP:TSLPR complexation.

Cutting Edge: Processing of Oxidized Peptides in Macrophages Regulates T Cell Activation and Development of Autoimmune Arthritis.

APCs are known to produce NADPH oxidase (NOX) 2-derived reactive oxygen species; however, whether and how NOX2-mediated oxidation affects redox-sensitive immunogenic peptides remains elusive. In this study, we investigated a major immunogenic peptide in glucose-6-phosphate isomerase (G6PI), a potential autoantigen in rheumatoid arthritis, which can form internal disulfide bonds. Ag presentation assays showed that presentation of this G6PI peptide was more efficient in NOX2-deficient (Ncf1m1J/m1J mutant) mice, compared with wild-type controls. IFN-γ-inducible lysosomal thiol reductase (GILT), which facilitates disulfide bond-containing Ag processing, was found to be upregulated in macrophages from Ncf1 mutant mice. Ncf1 mutant mice exhibited more severe G6PI peptide-induced arthritis, which was accompanied by the increased GILT expression in macrophages and enhanced Ag-specific T cell responses. Our results show that NOX2-dependent processing of the redox-sensitive autoantigens by APCs modify T cell activity and development of autoimmune arthritis.

Imiquimod-induced psoriasis-like inflammation in differentiated Human keratinocytes: Its evaluation using curcumin.

Psoriasis is considered to be a systemic disease of immune dysfunction. It is still unclear what triggers the inflammatory cascade associated with psoriasis but recent evidences suggest the vital role of IL-23/IL-17A cytokine axis in etiology of psoriasis. Several studies have been conducted in psoriatic-like animal models but ethical issues and complexity surrounding it halts the screening of new anti-psoriatic drug candidates. Hence, in this study, we developed a new in-vitro model for psoriasis using imiquimod (IMQ) induced differentiated HaCaT cells which could be used for screening of new anti-psoriatic drug candidates. The differentiated HaCaT cells were treated with IMQ (100µM) to induce psoriatic like inflammation and its effect was investigated using a natural anti-psoriatic compound, curcumin. The proliferation of psoriatic-like cells was inhibited by curcumin at 25 and 50µM concentrations. The psoriatic-like cells decreased in number with increase in apoptotic and dead cells upon curcumin treatment. Curcumin inhibited the proliferation of IMQ-induced differentiated HaCaT cells (Psoriatic-like cells) by down-regulation of pro-inflammatory cytokines, interleukin-17, tumor necrosis factor-α, interferon-γ, and interleukin-6. Apart from this, curcumin significantly enhanced the skin-barrier function by up-regulation of involucrin (iNV) and filaggrin (FLG), the regulators of epidermal skin barrier. The IMQ-induced differentiated HaCaT in vitro model recapitulated some aspects of the psoriasis pathogenesis similar to murine model. Henceforth, we conclude that this model may be used for rapid screening of anti-psoriatic drug candidates and warrant further mechanistic studies.

NAD+ repletion improves muscle function in muscular dystrophy and counters global PARylation.

Neuromuscular diseases are often caused by inherited mutations that lead to progressive skeletal muscle weakness and degeneration. In diverse populations of normal healthy mice, we observed correlations between the abundance of mRNA transcripts related to mitochondrial biogenesis, the dystrophin-sarcoglycan complex, and nicotinamide adenine dinucleotide (NAD+) synthesis, consistent with a potential role for the essential cofactor NAD+ in protecting muscle from metabolic and structural degeneration. Furthermore, the skeletal muscle transcriptomes of patients with Duchene's muscular dystrophy (DMD) and other muscle diseases were enriched for various poly[adenosine 5'-diphosphate (ADP)-ribose] polymerases (PARPs) and for nicotinamide N-methyltransferase (NNMT), enzymes that are major consumers of NAD+ and are involved in pleiotropic events, including inflammation. In the mdx mouse model of DMD, we observed significant reductions in muscle NAD+ levels, concurrent increases in PARP activity, and reduced expression of nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme for NAD+ biosynthesis. Replenishing NAD+ stores with dietary nicotinamide riboside supplementation improved muscle function and heart pathology in mdx and mdx/Utr-/- mice and reversed pathology in Caenorhabditis elegans models of DMD. The effects of NAD+ repletion in mdx mice relied on the improvement in mitochondrial function and structural protein expression (α-dystrobrevin and δ-sarcoglycan) and on the reductions in general poly(ADP)-ribosylation, inflammation, and fibrosis. In combination, these studies suggest that the replenishment of NAD+ may benefit patients with muscular dystrophies or other neuromuscular degenerative conditions characterized by the PARP/NNMT gene expression signatures.

Eupatorium lindleyanum DC. sesquiterpenes fraction attenuates lipopolysaccharide-induced acute lung injury in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Eupatorium lindleyanum DC. is widely used for its efficiency in treating cough, tracheitis and tonsillitis. Acute lung injury (ALI) induced by lipopolysaccharide (LPS) in mice was used to investigate therapeutic effects and possible mechanism of the sesquiterpenes fraction of E. lindleyanum DC. (EUP-SQT). MATERIALS AND METHODS: Mice were orally administrated with EUP-SQT (15, 30 and 60mg/kg) per day for 7 days consecutively before LPS challenge. The lung specimens and bronchoalveolar lavage fluid (BALF) were harvested for histopathological examinations and biochemical analysis at 6h and 24h after LPS challenge. The level of complement 3 (C3) and complement 3c (C3c) in serum was quantified by a sandwich ELISA kit. RESULTS: Pretreatment with EUP-SQT could significantly decrease lung wet-to-dry weight (W/D) ratio, nitric oxide (NO) and protein concentration in BALF, which was exhibited together with the lowered myeloperoxidase (MPO) activity, the increased superoxide dismutase (SOD) activity and down-regulation the level of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1ß (IL-1ß) in ALI model. Additionally, EUP-SQT attenuated lung histopathological changes and significantly reduced complement deposition with decreasing the level of C3 and C3c in serum. CONCLUSIONS: These results showed that EUP-SQT significantly attenuated LPS-induced ALI via reducing productions of pro-inflammatory mediators and decreasing the level of complement, indicating it as a potential therapeutic agent for ALI.

Tuberostemonine N, an active compound isolated from Stemona tuberosa, suppresses cigarette smoke-induced sub-acute lung inflammation in mice.

OBJECTIVE: Our previous study demonstrated that a Stemona tuberosa extract had significant effects on cigarette smoking (CS)-induced lung inflammation in mice. The present study evaluated the potential of tuberostemonine N (T.N) to prevent airway inflammation and suppress airway responses in a CS-induced in vivo COPD model. METHODS: T.N was isolated from the root of ST and analyzed using 1D and 2D NMR. The purity of T.N was accessed using HPLC-ELSD analysis. C57BL/6 mice in this study were whole-body exposed to mainstream CS or room air for 4 weeks, and T.N (1, 5 and 10 mg/kg body wt.) was administered to mice via intraperitoneal (i.p.) injection before CS exposure. The number of inflammatory cells, including neutrophils, macrophages and lymphocytes, and the amount of proinflammatory cytokines and chemokines were accessed from bronchoalveolar lavage fluid (BALF) to investigate the anti-inflammatory effects of T.N. Average alveoli size was also measured using histological analyses. RESULTS: Cellular profiles and histopathological analyses revealed that the infiltration of peribronchial and perivascular inflammatory cells decreased significantly in the T.N-treated groups compared to the CS-exposed control group. T.N significantly inhibited the secretion of proinflammatory cytokines and chemokines in BALF and decreased alveoli size in lung tissue. CONCLUSIONS: These data suggest that T.N exerts anti-inflammatory effects against airway inflammation, and T.N may be a novel therapeutic agent for lung diseases, such as COPD.

[[Effect of lanthanum chloride on cytokines expression of RAW264.7 induced by alumina ceramic particles].

OBJECTIVE: To investigate the relationship between alumina ceramic particles and aseptic loosening of the joint prosthesis and the effect of lanthanum chloride on the secretion of interleukin 1ß (IL-1ß) and tumor necrosis factor α (TNF-α) of macrophage RAW264.7 induced by alumina ceramic particles. METHODS: RAW264.7 cells were cultured in vitro and divided randomly into 4 groups according to different culture solutions: blank control group (group A), 1 mg/mL alumina ceramic particles (group B), 1 mg/mL alumina ceramic particles and 10 µmol/L lanthanum chloride (group C), and 10 µmol/L lanthanum chloride (group D). The cell growth was detected by MTT, and ELISA, RT-PCR, and Western blot were used to test the expressions of IL-1ß, TNF-α, and nuclear factor κB (NF-κB). RESULTS: There was no significant difference in cell growth among all groups by MTT (F = 2.180, P = 0.142). RT-PCR results showed that the expressions of IL-1ß, TNF-α, and NF-κB mRNA in group B were significantly higher than those in the other 3 groups (P < 0.05); the expressions in group D were significantly lower than those in group A (P < 0.05). ELISA results showed that the contents of IL-1ß and TNF-α in group B were significantly higher than those in the other 3 groups (P < 0.05); the contents in group D were significantly lower than those in group A (P < 0.05). Western blot analysis revealed that the expression of NF-κB protein in group B was significantly higher than that in the other 3 groups (P < 0.05). CONCLUSION: Alumina ceramic particles can stimulate the secretion of IL-1ß and TNF-α of macrophage, and lanthanum chloride can inhibit the secretion of IL-1ß and TNF-α of macrophage.

Insights into the inhibition and mechanism of compounds against LPS-induced PGE2 production: a pathway network-based approach and molecular dynamics simulations.

In comparison to the current target-based screening approach, it is increasingly evident that active lead compounds based on disease-related phenotypes are more likely to be translated to clinical trials during drug development. That is, because human diseases are in essence the outcome of the abnormal function of multiple genes, especially in complex diseases. Therefore, as a conventional technology in the early phase of active lead compound discovery, computational methods that can connect molecular interactions and disease-related phenotypes to evaluate the efficacy of compounds are in urgently required. In this work, a computational approach that integrates molecular docking and pathway network analysis (network efficiency and network flux) was developed to evaluate the efficacy of a compound against LPS-induced Prostaglandin E2(PGE2) production. The predicted results were then validated in vitro, and a correlation with the experimental results was analyzed using linear regression. In addition, molecular dynamics (MD) simulations were performed to explore the molecular mechanism of the most potent compounds. There were 12 hits out of 28 predicted ingredients separated from Reduning injection (RDN). The predicted results have a good agreement with the experimental inhibitory potency (IC50) (correlation coefficient = 0.80). The most potent compounds could target several proteins to regulate the pathway network. This might partly interpret the molecular mechanism of RDN on fever. Meanwhile, the good correlation of the computational model with the wet experimental results might bridge the gap between molecule-target interactions and phenotypic response, especially for multi-target compounds. Therefore, it would be helpful for active lead compound discovery, the understanding of the multiple targets and synergic essence of traditional Chinese medicine (TCM).

Pierced Lasso Bundles are a new class of knot-like motifs.

A four-helix bundle is a well-characterized motif often used as a target for designed pharmaceutical therapeutics and nutritional supplements. Recently, we discovered a new structural complexity within this motif created by a disulphide bridge in the long-chain helical bundle cytokine leptin. When oxidized, leptin contains a disulphide bridge creating a covalent-loop through which part of the polypeptide chain is threaded (as seen in knotted proteins). We explored whether other proteins contain a similar intriguing knot-like structure as in leptin and discovered 11 structurally homologous proteins in the PDB. We call this new helical family class the Pierced Lasso Bundle (PLB) and the knot-like threaded structural motif a Pierced Lasso (PL). In the current study, we use structure-based simulation to investigate the threading/folding mechanisms for all the PLBs along with three unthreaded homologs as the covalent loop (or lasso) in leptin is important in folding dynamics and activity. We find that the presence of a small covalent loop leads to a mechanism where structural elements slipknot to thread through the covalent loop. Larger loops use a piercing mechanism where the free terminal plugs through the covalent loop. Remarkably, the position of the loop as well as its size influences the native state dynamics, which can impact receptor binding and biological activity. This previously unrecognized complexity of knot-like proteins within the helical bundle family comprises a completely new class within the knot family, and the hidden complexity we unraveled in the PLBs is expected to be found in other protein structures outside the four-helix bundles. The insights gained here provide critical new elements for future investigation of this emerging class of proteins, where function and the energetic landscape can be controlled by hidden topology, and should be take into account in ab initio predictions of newly identified protein targets.

Cloning and gene expression of allograft inflammatory factor-1 (AIF-1) provide new insights into injury and bacteria response of the sea cucumber Apostichopus japonicus (Selenka, 1867).

Allograft inflammatory factor-1 (AIF-1) is an interferon (IFN)-γ-inducible Ca(2+)-binding cytokine that associates with the immune defense and inflammatory response. In this study, we reported AIF-1 gene in sea cucumber Apostichopus japonicus (AjAIF-1). The full-length cDNA of AjAIF-1 is 1541 bp with an open reading frame (ORF) of 477 bp encoding 158 amino acids. Two EF-hand Ca(2+)-binding motifs were found in the deduced AjAIF-1. AjAIF-1 was widely expressed in all tested tissues (body wall, intestine, respiratory tree, tube feet, coelomocytes and longitudinal muscle), with the highest expression in respiratory tree. After Vibrio splendidus challenge and physical injury, AjAIF-1 transcripts were significantly upregulated in coelomocytes. The mRNA expression level of AjAIF-1 in coelomocytes reached to the highest value at 4 h (3.38-folds vs. the PBS control, P < 0.05) post injection. After papilla injury, the mRNA level of AjAIF-1 in coelomocytes was upregulated, and its peak value was found at 4 h (3.88-folds vs. the control, P < 0.05). These results indicated that 1) AjAIF-1 sensitively responds to pathogen infection; 2) AjAIF-1 is involved in acute inflammatory response. Our findings gain general information about the role of AjAIF-1 in the innate immunity of A. japonicus.

Protective mechanism of lignans from Phyllanthus amarus against galactosamine/ lipopolysaccharide-induced hepatitis: an in-vivo and in-silico studies.

Phyllanthus amarus is a medicinal herb used in traditional Indian medicine for liver disorders. Several researches also show that it acts primarily in the liver, but the molecules were unidentified for liver protective activity. This study was to determine whether the lignans isolated from P. amarus attenuates the D-galactosamine (GalN) / Lipopolysaccharide (LPS)- induced acute hepatitis in mice. Standardize mixture of lignans (slPA) isolated from leaves of P. amarus using automated chromatographic technique was used for experiments. Experimental mice were orally pre-treated with slPA (10, 30 and 100 mg/kg) for 7 days before intra-peritoneal injection of GalN/LPS. Acute hepatitis in mice was confirmed by significant increase of pro-inflammatory cytokines, and hepatotoxic markers. Pre-treatment of slPA exhibit significant liver protection in dose dependant mannaer. In-silico molecular docking studies also suggests that lignans are preferentially more active due to strong binding affinity against pro-inflammatory cytokines; IL-1ß, IL-6, and TNF-α. The electronic parameters of lignans for bioavailability, drug likeness and toxicity were within the acceptable limit. In-vivo and in-silico results suggest that pretreatment of slPA exhibit potent hepatoprotection against GalN/LPS-induced hepatitis in mice and the liver protective effects may be due to the inhibition of inflammatory mediators.

Cytokines in radiobiological responses: a review.

Cytokines function in many roles that are highly relevant to radiation research. This review focuses on how cytokines are structurally organized, how they are induced by radiation, and how they orchestrate mesenchymal, epithelial and immune cell interactions in irradiated tissues. Pro-inflammatory cytokines are the major components of immediate early gene programs and as such can be rapidly activated after tissue irradiation. They converge with the effects of ionizing radiation in that both generate free radicals including reactive oxygen and nitrogen species (ROS/RNS). "Self" molecules secreted or released from cells after irradiation feed the same paradigm by signaling for ROS and cytokine production. As a result, multilayered feedback control circuits can be generated that perpetuate the radiation tissue damage response. The pro-inflammatory phase persists until such times as perceived challenges to host integrity are eliminated. Antioxidant, anti-inflammatory cytokines then act to restore homeostasis. The balance between pro-inflammatory and anti-inflammatory forces may shift to and fro for a long time after radiation exposure, creating waves as the host tries to deal with persisting pathogenesis. Individual cytokines function within socially interconnected groups to direct these integrated cellular responses. They hunt in packs and form complex cytokine networks that are nested within each other so as to form mutually reinforcing or antagonistic forces. This yin-yang balance appears to have redox as a fulcrum. Because of their social organization, cytokines appear to have a considerable degree of redundancy and it follows that an elevated level of a specific cytokine in a disease situation or after irradiation does not necessarily implicate it causally in pathogenesis. In spite of this, "driver" cytokines are emerging in pathogenic situations that can clearly be targeted for therapeutic benefit, including in radiation settings. Cytokines can greatly affect intrinsic cellular radiosensitivity, the incidence and type of radiation tissue complications, bystander effects, genomic instability and cancer. Minor and not so minor, polymorphisms in cytokine genes give considerable diversity within populations and are relevant to causation of disease. Therapeutic intervention is made difficult by such complexity; but the potential prize is great.