Spatial distribution of sand fly species (Psychodidae: Phlebtominae), ecological niche,and climatic regionalization in zoonotic foci of cutaneous leishmaniasis,southwest of Iran

Cutaneous leishmaniasis (CL) is a complex vector‐borne disease caused by Leishmania parasites that are transmitted by the bite of several species of infected female phlebotomine sand flies. Monthly factor analysis of climatic variables indicated fundamental variables. Principal component‐based regionalization was used for recognition of climatic zones using a clustering integrated method that identified five climatic zones based on factor analysis. To investigate spatial distribution of the sand fly species, the kriging method was used as an advanced geostatistical procedure in the ArcGIS modeling system that is beneficial to design measurement plans and to predict the transmission cycle in various regions of Khuzestan province, southwest of Iran. However, more than an 80% probability of P. papatasi was observed in rainy and temperate bio‐climatic zones with a high potential of CL transmission. Finding P. sergenti revealed the probability of transmission and distribution patterns of a non‐native vector of CL in related zones. These findings could be used as models indicating climatic zones and environmental variables connected to sand fly presence and vector distribution. Furthermore, this information is appropriate for future research efforts into the ecology of Phlebotomine sand flies and for the prevention of CL vector transmission as a public health priority.     

Computational Design of TrkB Peptide Inhibitors and Their Biological Effects on Ovarian Cancer Cell Lines

There are large numbers of different intracellular signaling pathways regulated by Tyrosine kinases (Trk) receptors. Trk receptors, especially TrkB, are also frequently overexpressed in a variety of human malignant tumors. In this study, we have computationally designed small peptide-based inhibitors of TrkB and investigated their effects on the proliferation and apoptosis of two ovarian cancer cell lines. Molecular docking of TrkB with its ligand and antagonist, BDNF and Cyclotraxin B respectively, was carried out using HADDOCK program. A peptide library was constructed based on the critical residues involved in the TrkB binding site. After docking and optimization, two selected peptides were purchased and their effects on the viability and apoptosis of the cells were evaluated by performing MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) test and flow cytometry assay. Subsequently, the levels of expression and phosphorylation statues of TrkB and its two downstream genes including MAPK3 and eIF4E were assessed with western blot. We found that designed peptides effectively reduced TrkB, MAPK3 and eIF4E phosphorylation, reduced cell viability and induced apoptosis in the treated cells when compared to untreated cells. In conclusion, the BDNF/TrkB signaling is shown to be attenuated substantially in the presence of peptide inhibitors suggesting a strong inhibitory potential of the designed peptides for Trk family.     

Stimulating effect of both 4’‐O‐methylnorbelladine feeding and temporary immersion conditions on galanthamine and lycorine production by Leucojum aestivum L. bulblets

Bulb cultures of Leucojum aestivum and L. aestivum ‘Gravety Giant’ were subcultured in medium containing the precursor 4’‐O‐methylnorbelladine (MN) at various concentrations [0 (control), 0.15 and 0.3 g/L]. The cultures were conducted in bioreactor RITA® and lasted for 15, 30, 40 and 50 days. The growth rate and the alkaloid accumulation in bulblets were studied. For this latter purpose, a purification method was developed. It comprised a highly selective solid phase extraction using on the one hand, UPTI‐CLEAN SI and SCX cartridges for plant extracts and on the other hand, 2H cartridges for culture media. Pure alkaloidal fractions were, thus, analyzed by LC‐ESI‐MS allowing the quantitative evaluation of galanthamine and lycorine from culture extracts. Precursor feeding along with temporary immersion conditions was found to significantly improve the accumulation of both galanthamine and lycorine. The maximal concentrations of galanthamine (0.81 mg/g DW) and lycorine (0.54 mg/g DW) in L. aestivum bulblets were reached, respectively, after 40 days of culture with 0.15 g/L of precursor and after 30 days of culture with 0.3 g/L of precursor. In L. aestivum ‘Gravety Giant’ bulb cultures, 0.3 g/L of precursor was the best condition for both galanthamine (0.6 mg/g DW after 50 days) and lycorine (1.13 mg/g DW after 30 days).     

Finding neoepitopes in mouse models of personalized cancer immunotherapy

Background

Cancer immunotherapy uses one’s own immune system to fight cancerous cells. As immune system is hard-wired to distinguish self and non-self, cancer immunotherapy is predicted to target cancerous cells specifically, therefore is less toxic than chemotherapy and radiation therapy, two major treatments for cancer. Cancer immunologists have spent decades to search for the specific targets in cancerous cells.

Methods

Due to the recent advances in high throughput sequencing and bioinformatics, evidence has merged that the neoantigens in cancerous cells are probably the cancer-specific targets that lead to the destruction of cancer.We will review the transplantable murine tumor models for cancer immunotherapy and the bioinformatics tools used to navigate mouse genome to identify tumor-rejecting neoantigens.

Results

Several groups have independently identified point mutations that can be recognized by T cells of host immune system. It is consistent with the note that the formation of peptide-MHC I-TCR complex is critical to activate T cells. Both anchor residue and TCR-facing residue mutations have been reported. While TCR-facing residue mutations may directly activate specific T cells, anchor residue mutations improve the binding of peptides to MHC I molecules, which increases the presentation of peptides and the T cell activation indirectly.

Conclusions

Our work indicates that the affinity of neoepitopes for MHC I is not a predictor for anti-tumor immune responses in mice. Instead differential agretopic index (DAI), the numerical difference of epitope-MHC I affinities between the mutated and un-mutated sequences is a significant predictor. A similar bioinformatics pipeline has been developed to generate personalized vaccines to treat human ovarian cancer in a Phase I clinical trial.

     

Effects of alternate RNA splicing on glucokinase isoform activities in the pancreatic islet, liver, and pituitary

Different glucokinase isoforms are produced by tissue-specific alternative RNA splicing in the liver and pancreatic islet, the only tissues in which glucokinase activity has been detected. To determine whether differences in protein structure brought about by alternative RNA splicing have an effect on glucose phosphorylating activity, we expressed cDNAs encoding four different hepatic and islet glucokinase isoforms and determined the Km and Vmax of each. When the glucokinase B1 and L1 isoforms were expressed in eukaryotic cells, both high Km glucose phosphorylating activity and immunoreactive protein were detected. However, when the glucokinase B2 and L2 isoforms were expressed, both of which differ by deletion of 17 amino acids in a region between the putative glucose and ATP-binding domains, no high Km glucose phosphorylating activity and much less immunoreactive protein were detected. When the glucokinase B1 and B2 isoforms were expressed in Escherichia coli as fusion proteins with glutathione S-transferase, affinity-purified B1 fusion protein was able to phosphorylate glucose whereas the B2 fusion protein was not, thus indicating that the lack of glucose phosphorylating activity from both the B2 and L2 isoforms is due to lack of intrinsic activity in addition to accumulation of less protein. The Km values of the B1 and L1 isoforms, which differ from each other by 15 amino acids at the NH2 terminus, were similar, but the Vmax of the B1 isoform was 2.8-fold higher than that of the L1 isoform. Mutagenesis of the first two potential initiation codons in the glucokinase B1 cDNA from ATG to GTC (methionine to valine) indicated that the first ATG was crucial for activity and is, therefore, the likely translation initiation codon. Messenger RNAs encoding both the B2 and L2 isoforms of glucokinase were detected in islet and liver by polymerase chain reaction amplification of total cDNA, indicating that mRNAs utilizing this weak alternate splice acceptor site in the fourth exon are normally present in both the liver and islet but as minor components. A regulatory role for weak alternate splice acceptor and donor sites in the glucokinase gene was suggested by examining the expression of the gene in the pituitary and in AtT-20 cells. Interestingly, although glucokinase mRNAs of appropriate sizes were detected in both the AtT-20 cells and rat pituitaries, neither exhibited any detectable high Km glucose phosphorylating activity.(ABSTRACT TRUNCATED AT 400 WORDS)     

Coevolution of antibiotic production and counter‐resistance in soil bacteria

We present evidence for the coexistence and coevolution of antibiotic resistance and biosynthesis genes in soil bacteria. The distribution of the streptomycin (strA) and viomycin (vph) resistance genes was examined in Streptomyces isolates. strA and vph were found either within a biosynthetic gene cluster or independently. Streptomyces griseus strains possessing the streptomycin cluster formed part of a clonal complex. All S. griseus strains possessing solely strA belonged to two clades; both were closely related to the streptomycin producers. Other more distantly related S. griseus strains did not contain strA. S. griseus strains with only vph also formed two clades, but they were more distantly related to the producers and to one another. The expression of the strA gene was constitutive in a resistance‐only strain whereas streptomycin producers showed peak strA expression in late log phase that correlates with the switch on of streptomycin biosynthesis. While there is evidence that antibiotics have diverse roles in nature, our data clearly support the coevolution of resistance in the presence of antibiotic biosynthetic capability within closely related soil dwelling bacteria. This reinforces the view that, for some antibiotics at least, the primary role is one of antibiosis during competition in soil for resources.     

Curcumin as an anti-inflammatory agent: Implications to radiotherapy and chemotherapy

Cancer is the second cause of death worldwide. Chemotherapy and radiotherapy are the most common modalities for the treatment of cancer. Experimental studies have shown that inflammation plays a central role in tumor resistance and the incidence of several side effects following both chemotherapy and radiotherapy. Inflammation resulting from radiotherapy and chemotherapy is responsible for adverse events such as dermatitis, mucositis, pneumonitis, fibrosis, and bone marrow toxicity. Chronic inflammation may also lead to the development of second cancer during years after treatment. A number of anti-inflammatory drugs such as nonsteroidal anti-inflammatory agents have been proposed to alleviate chronic inflammatory reactions after radiotherapy or chemotherapy. Curcumin is a well-documented herbal anti-inflammatory agents. Studies have proposed that curcumin can help management of inflammation during and after radiotherapy and chemotherapy. Curcumin targets various inflammatory mediators such as cyclooxygenase-2, inducible nitric oxide synthase, and nuclear factor κB (NF-κB), thereby attenuating the release of proinflammatory and profibrotic cytokines, and suppressing chronic production of free radicals, which culminates in the amelioration of tissue toxicity. Through modulation of NF-κB and its downstream signaling cascade, curcumin can also reduce angiogenesis, tumor growth, and metastasis. Low toxicity of curcumin is linked to its cytoprotective effects in normal tissues. This protective action along with the capacity of this phytochemical to sensitize tumor cells to radiotherapy and chemotherapy makes it a potential candidate for use as an adjuvant in cancer therapy. There is also evidence from clinical trials suggesting the potential utility of curcumin for acute inflammatory reactions during radiotherapy such as dermatitis and mucositis.     

Cyclooxygenase-2 in cancer: A review

Cyclooxygenase-2 (COX-2) is frequently expressed in many types of cancers exerting a pleiotropic and multifaceted role in genesis or promotion of carcinogenesis and cancer cell resistance to chemo- and radiotherapy. COX-2 is released by cancer-associated fibroblasts (CAFs), macrophage type 2 (M2) cells, and cancer cells to the tumor microenvironment (TME). COX-2 induces cancer stem cell (CSC)-like activity, and promotes apoptotic resistance, proliferation, angiogenesis, inflammation, invasion, and metastasis of cancer cells. COX-2 mediated hypoxia within the TME along with its positive interactions with YAP1 and antiapoptotic mediators are all in favor of cancer cell resistance to chemotherapeutic drugs. COX-2 exerts most of the functions through its metabolite prostaglandin E2. In some and limited situations, COX-2 may act as an antitumor enzyme. Multiple signals are contributed to the functions of COX-2 on cancer cells or its regulation. Members of mitogen-activated protein kinase (MAPK) family, epidermal growth factor receptor (EGFR), and nuclear factor-κβ are main upstream modulators for COX-2 in cancer cells. COX-2 also has interactions with a number of hormones within the body. Inhibition of COX-2 provides a high possibility to exert therapeutic outcomes in cancer. Administration of COX-2 inhibitors in a preoperative setting could reduce the risk of metastasis in cancer patients. COX-2 inhibition also sensitizes cancer cells to treatments like radio- and chemotherapy. Chemotherapeutic agents adversely induce COX-2 activity. Therefore, choosing an appropriate chemotherapy drugs along with adjustment of the type and does for COX-2 inhibitors based on the type of cancer would be an effective adjuvant strategy for targeting cancer.