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Optimizing synthetic antimicrobial peptides for safe and enhanced activity against fungal and bacterial pathogens is useful for genetic engineering of plants for resistance to plant pathogens and their associated mycotoxins. Nine synthetic peptides modeled after lytic peptides tachyplesin 1, D4E1 from cecropin A and protegrin 1 were added to germinated spores of fungal species Aspergillus flavus, Rhizopus stolonifer, Fusarium oxysporum f. sp. vasinfectum, F. verticillioides, F. graminearum, Claviceps purpurea, Verticillium dahliae, Thielaviopsis basicola and bacterial cultures of Psuedomonas syringae p.v. tabaci and Xanthomonas campestris p.v. campestris at different doses and inhibitory dose response curves were modeled to assess antimicrobial activity. Peptides GV185 and GV187, modified from tachyplesin 1, had superior abilities to inhibit fungal and bacterial growth (50% inhibitory concentrations or IC50 ranging from 0.1 to 8.7 µM). Rhizopus stolonifer (IC50 = 8.1 µM), A. flavus (IC50 = 3.1 µM) and F. graminearum (IC50 = 2.2 µM) were less inhibited by GV185 and GV187 than all the remaining fungi (IC50 = 1.4 µM) and bacteria (IC50 = 0.1 µM). Of the remaining peptides, GV193, GV195 and GV196 (IC50 range 0.9 to 6.6 µM) inhibited fungal growth of A. flavus, F. verticillioides and F. graminearum less than GV185 and GV187 (IC50 range 0.8 to 3.9 µM), followed by GV197 (IC50 range 0.8 - 9.1 µM) whereas GV190 and GV192 inhibited poorly (IC50 range 28.2 to 36.6 µM and 15.5 to 19.4 µM, respectively) and GV198 stimulated growth. GV185 and GV187 had slightly weaker hydrophobic and cationic residues than other tachyplesin 1 modified peptides, but still had unexpectedly high lytic activity. Germinated fungal spores of R. stolonifer and F. graminearum exposed to these two peptides and D4E1 and AGM182 appeared wrinkled with perforations near potential cytoplasmic leakage, which provided evidence of plasma membrane and cell wall lysis. We conclude that peptides GV185 and GV187 are promising candidates for genetic engineering of crops for resistance to plant pathogenic bacteria and fungi including A. flavus and aflatoxin contamination.

Activated M2 polarized macrophages are drivers of pulmonary fibrosis in several clinical scenarios such as Acute Respiratory Disease Syndrome (ARDS) and Idiopathic Pulmonary Fibrosis (IPF), through the production of inflammatory and fibrosis-inducing cytokines. In this study, we investigated the effect of targeting the CD206 receptor with a novel fragment of a Host Defense Peptide (HDP), RP-832c to decrease cytokines that cause fibrosis. RP-832c selectively binds to CD206 on M2 polarized bone marrow derived macrophages (BMDM) in vitro, resulting in a time-dependent decrease in CD206 expression, and a transient increase in M1 marker TNFα, which resolves over a 24hr period. To elucidate the antifibrotic effect of RP-832c, we used a murine model of bleomycin (BLM) -induced early-stage pulmonary fibrosis. RP-832c significantly reduced bleomycin-induced fibrosis in a dosage dependent manner, as well as decreased CD206, TGF-β1 and α-SMA expression in mouse lungs. Interestingly we did not observe any changes in the resident alveolar macrophage marker CD170 expression. Similarly, in an established model of lung fibrosis, RP-832c significantly decreased fibrosis in the lung, as well as significantly decreased inflammatory cytokines TNFα, IL-6, IL-10, INF-γ, CXCL1/2, and fibrosis markers TGF-β1 and MMP-13. In comparison with FDA approved drugs, Nintedanib and Pirfenidone, RP-832c exhibited a similar reduction in fibrosis compared to Pirfenidone, and to a greater extent than Nintedanib, with no apparent toxicities observed on body weight or blood chemistry. In summary, RP-832c is a potential agent to mitigate the overactivity of M2 macrophages in pathogenesis several pulmonary fibrotic diseases, including SARS-CoV-2 induced lung fibrosis.

Solid tumors elicit a detectable immune response including the infiltration of tumor-associated macrophages (TAMs). Unfortunately, this immune response is co-opted into contributing toward tumor growth instead of preventing its progression. We seek to reestablish an antitumor immune response by selectively targeting surface receptors and endogenous signaling processes of the macrophage subtypes driving cancer progression. RP-182 is a synthetic 10-mer amphipathic analog of host defense peptides that selectively induces a conformational switch of the mannose receptor CD206 expressed on TAMs displaying an M2-like phenotype. RP-182-mediated activation of this receptor in human and murine M2-like macrophages elicits a program of endocytosis, phagosome-lysosome formation, and autophagy and reprograms M2-like TAMs to an antitumor M1-like phenotype. In syngeneic and autochthonous murine cancer models, RP-182 suppressed tumor growth, extended survival, and was an effective combination partner with chemo- or immune checkpoint therapy. Antitumor activity of RP-182 was also observed in CD206(high) patient-derived xenotransplantation models. Mechanistically, via selective reduction of immunosuppressive M2-like TAMs, RP-182 improved adaptive and innate antitumor immune responses, including increased cancer cell phagocytosis by reprogrammed TAMs.

Objective Toxoplasma gondii, an intracellular zoonotic parasite, infects approximately a third of the world population. Current drugs for treatment of T. gondii infection have been challenged with ineffectiveness and adverse side effects. This necessitates development of new anti-Toxoplasma drugs. Sorghum bicolor [Moench] leaf extract has been used in African traditional medicine for the management of anemia and treatment of infectious diseases. We tested the in vitro anti-Toxoplasma inhibitory activity of S. bicolor’s oil-like crude extracts and fractions against T. gondii and determined their cytotoxic effects on human host cells. Results Significant inhibitory activities against the growth of T. gondii tachyzoites were observed for the crude extract (IC50 = 3.65 µg/mL), the hexane-methanol fraction (IC50 = 2.74 µg/mL), and the hexane fraction (IC50 = 3.55 µg/mL) after 48 h of culture. The minimum cytotoxicity concentrations against HFF were 34.41, 16.92 and 7.23 µg/mL for crude extract, hexane-methanol and hexane fractions, respectively. The crude extract and fractions showed high antiparasitic effects with low cytotoxic effects. Further studies to determine synergistic activities and modes of action would provide impetus for the development of new toxoplasmosis drugs or nutraceuticals.

Background In systemic sclerosis, activated macrophages having M2-like properties are believed to contribute to the fibrotic pathology by secreting profibrotic factors such as TGFβ. Certain synthetic peptides (10-12mers) studied here coopt the mechanism used by macrophages to detect bacteria by binding to certain regions of CD206, a receptor highly expressed in the M2 macrophages, and repolarise them to an M1 phenotype. Objectives We aimed to determine the macrophage activation signature in SSc, assess CD206 as a biomarker of ongoing fibrotic activity, and measure the effect of the peptides on macrophage activation and macrophage-fibroblast cross-talk. Methods: sCD206 was assayed in plasma (n=50 healthy, 50 limited SSc, 50 diffuse SSc), and suction blister fluid (BF) obtained over active lesions by ELISA. sSIGLEC (monocyte interferon signature) and IL-31 (Th2 signature) were assayed for comparison. Cell surface CD206 and DAMP receptor P2X7, were assayed by flow cytometry. The macrophage activation signature was investigated further by qPCR for inflammatory M1, as well as M2-like gene expression (IFNγ, Arg1, CD2106). Macrophage-fibroblast cross talk was assessed using media transfer following heat activation to SSc dermal fibroblasts assayed by qPCR for collagen I. The macrophage secretome was determined by Luminex and ELISA. Results CD206 was significantly elevated in SSc BF (SSc median sCD206 42, HC 31 pg/ml, p Conclusion A macrophage activation signature is identified in SSc patients, in proportion to the severity of disease. A mixed activation signature with inflammatory as well as pro-fibrotic M2-like properties is seen. RP peptides, which target the cells via CD206, reduce the activation signature and inhibit pro-fibrotic cross talk in these cells. Disclosure of Interests: Henry Lopez Shareholder of: Murigenics, Riptide Bioscience, Employee of: Pfizer, Kimti Kumar: None declared, George Martin Shareholder of: Riptide Bioscience, Jesse Jaynes Shareholder of: Riptide Bioscience, James Stanway: None declared, Bahja Ahmed Abdi: None declared, Nikita Arumalla: None declared, Sarah Karrar: None declared, Sian Morris: None declared, Christopher Denton Grant/research support from: GlaxoSmithKline, Inventiva, CSF Behring, Consultant for: Roche-Genentech, Actelion, GlaxoSmithKline, Sanofi Aventis, Inventiva, CSL Behring, Boehringer Ingelheim, Bayer, David Abraham: None declared, Xu Shiwen: None declared, Richard Stratton: None declared

The relentless growth of multidrug resistance and generation of recalcitrant biofilm are major obstacles in treating wounds, particularly in austere military environments where broad-spectrum pathogen coverage is needed. Designed antimicrobial peptides (dAMPs) are constructed analogs of naturally occurring AMPs that provide the first line of defense in many organisms. RP557 is a dAMP resulting from iterative rational chemical structural analoging with endogenous AMPs, human cathelicidin LL-37 and Tachyplesin 1 and the synthetic D2A21 used as structural benchmarks. RP557 possesses broad spectrum activity against Gram-positive and Gram-negative bacteria and fungi, including recalcitrant biofilm with substantial selective killing over bacterial cells compared to mammalian cells. RP557 did not induce resistance following chronic passages of Pseudomonas aeruginosa and Staphylococcus aureus at subinhibitory concentrations, whereas concurrently run conventional antibiotics, gentamycin, and clindamycin, did. Furthermore, RP557 was able to subsequently eliminate the generated gentamycin resistant P. aeruginosa and clindamycin resistant S. aureus strains without requiring an increase in minimum inhibitory concentration (MIC) concentrations. RP557 was evaluated further in a MRSA murine wound abrasion infection model with a topical application of 0.2% RP557, completely eliminating infection. If these preclinical results are translated into the clinical setting, RP557 may become crucial for the empirical broad-spectrum treatment of wound pathogens, so that infections can be reduced to a preventable complication of combat-related injuries.

We investigated dried red leaf extracts of Sorghum bicolor for activity against Toxoplasma gondii tachyzoites. S. bicolor red leaf extracts were obtained by bioassay-guided fractionation using ethanol and ethyl acetate as solvents. Analysis of the crude and fractionated extracts from S. bicolor using electrospray ionization mass spectrometry (ESI-MS) showed that they contained significant amounts of apigeninidin, luteolinidin, 7-methoxyapigeninidin, 5-methoxyapigeninidin, 5-methoxyluteolinidin, 7-methoxyluteolinidin 5,7-dimethoxyapigeninidin or 5,7-dimethoxyluteolinidin, based on mass per charge (m/z). When tested in vitro, the IC50s for inhibitory activity against T. gondii tachyzoites' growth of the ethanol and ethyl acetate extracts were 2.3- and 4-fold, respectively, lower than their cytotoxic IC50s in mammalian cells. Ethyl acetate extracts fractionated in chloroform-methanol and chloroform had IC50s against T. gondii that were 56.1- and 3-fold lower than their respective cytotoxic IC50s in mammalian cells. These antiparasitic activities were found to be consistent with those of the respective pure 3-deoxyanthocyanidin compounds identified to be contained in the fractions in significant amounts. Further, we observed that, the position and number of methoxy groups possessed by the 3-deoyanthocyanidins influenced their antiparasitic activity. Together, our findings indicate that S. bicolor red-leaf 3-deoxyanthocyanidins-rich extracts have potent in vitro inhibitory activity against the proliferative stage of T. gondii parasites.

Recurrent vulvovaginal candidiasis (RVVC) is a widespread chronic infection that has a substantial negative impact on work and quality of life. The development of antimicrobial resistance and biofilm formation are speculated to contribute to Candida pathogenicity and treatment ineffectiveness. Designed antimicrobial peptides (dAMPs) are chemically modified from endogenous antimicrobial peptides that provide the first line of defense against pathogens., Recurrent vulvovaginal candidiasis (RVVC) is a widespread chronic infection that has a substantial negative impact on work and quality of life. The development of antimicrobial resistance and biofilm formation are speculated to contribute to Candida pathogenicity and treatment ineffectiveness. Designed antimicrobial peptides (dAMPs) are chemically modified from endogenous antimicrobial peptides that provide the first line of defense against pathogens. The goal here is to identify a dAMP for the topical treatment of RVVC. The dAMP MICs were determined for 46 fluconazole-susceptible and fluconazole-resistant Candida spp. clinical isolates. The possibility of inducing dAMP drug resistance and comparison of dAMP and fluconazole activity against preformed Candida biofilm and biofilm formation were evaluated. Assessment of mammalian cell viability was determined using bioluminescent human keratinocytes. The dAMP effect on fungus was probed via scanning electron microscopy, and topically applied dAMP activity was evaluated in a rodent vulvovaginal candidiasis (VVC) infection model. dAMPs demonstrated broad-spectrum antimicrobial activity against common causative clinical Candida isolates, reduced preformed biofilm, and inhibited biofilm formation. An evaluated dAMP did not induce resistance after repeated exposure of Candida tropicalis. The dAMPs were selective for Candida cells with limited mammalian cytotoxicity with substantial activity in a rodent VVC model. dAMPs are described as having potent antifungal and antibiofilm activity, likely direct membrane action with selectivity for Candida cells, with limited resistance development. Combined with activity in a rodent VVC model, the data support clinical evaluation of dAMPs for topical treatment of VCC and recurrent VVC infections.

Synthetic host defense peptides (HDP) are a new class of promising therapeutic agents with potential application in a variety of diseases. RP-182 is a 10mer synthetic HDP design, which selectively reduces M2-like tumor associated macrophages via engagement with the cell surface lectin receptor MRC1/CD206 and is currently being developed as an innate immune defense regulator to improve anti-tumor immunity in immunologically cold tumors. Herein, we describe a sensitive and specific liquid chromatography (LC) coupled to quadrupole electron spray tandem mass spectrometry method to measure positively charged HDPs and HDP peptide fragments in complex biological matrices. Carboxylic acid magnetic beads were used as an affinity-capturing agent to extract the positively charged RP-182 from both mouse plasma and tissue homogenates. Beads were eluted with 0.1% (v/v) formic acid and chromatographic separation was achieved on a Waters 2.1 × 100 mm, 3.5 μm XSelect Peptide CSH C18 column with a Vanguard pre-column of the same phase. MS/MS was performed on a Thermo TSQ Quantiva triple quadrupole mass spectrometer operating in Selected Reaction Monitoring (SRM) mode fragmenting the plus three parent ion 458.9(+3) and monitoring ions 624.0(+2), 550.5(+2), and 597.3(+1) for RP-182 and 462.4(+3) > 629.1(+2), 555.5(+2), and 607.3(+1) for isotopic RP-182 standard. The assay had good linearity ranging from 1 ng to 1000 ng in mouse plasma with the lower limit of detection for RP-182 at 1 ng in mouse plasma with good intra- and inter-sample precision and accuracy. Recovery ranged from 66% to 77% with minimum matrix effects. The method was successfully applied to an abbreviated pharmacokinetic study in mice after single IP injection of RP-182. The method was successfully tested on a second HDP, the 17mer D4E1, and the cationic human peptide hormone ghrelin suggesting that it might be a general sensitive method applicable to quantifying HDP peptides that are difficult to extract.

The main pathogen of Gladiolus plants is Fusarium oxysporum, a soilborne fungus that infects roots and corms resulting in death of the plant. Purified D4E1, a synthetic antimicrobial peptide, was previously reported (De Lucca et al. 1998) to inhibit F. oxysporum spores from forming mycelial colonies in vitro at a concentration of 3 μM making it a candidate gene for genetic engineering of Gladiolus for resistance to F. oxysporum. Gladiolus cv. Peter Pears plants were transformed by particle bombardment with plasmid DNA containing a 90 bp D4E1 gene that was under the control of the duplicated CaMV 35S promoter. Five of the 14 independently transformed plant lines were evaluated for resistance to F. oxysporum. Transgenic plants were tested in vitro for resistance to F. oxysporum, and several lines appeared to be more resistant than the control plants that lacked D4E1. Cell extracts of transgenic Gladiolus lines 6(1) and 7(1) inhibited germinated spores of F. oxysporum f. sp. gladioli from forming mycelial colonies by 34 and 38 %, respectively, in vitro. F. oxysporum f. sp. gladioli was transformed with the ECFP (cyan) gene allowing us to follow the growth of F. oxysporum during infection of D4E1-transformed and non-transformed roots. Fluorescence observations using confocal laser scanning microscopy showed that 3–10 days after infection, F. oxysporum covered the surface of the root and formed pseudo-appressoria, but hyphae were never observed to penetrate cells of the root. Ten days after infection with F. oxysporum, non-transformed roots had completely disintegrated whereas transgenic roots of line 7(1) were just beginning to lose their cellular integrity. Cell extracts from the five transgenic lines showed either an inhibition of F. oxysporum mycelial colony formation or less fungal hyphae were observed to infect their roots as compared to non-transformed Gladiolus plants.

Purpose: To limit corneal damage and potential loss of vision, bacterial keratitis must be treated aggressively. Innovation in antimicrobials is required due to the need for empirical treatment and the rapid emergence of bacterial resistance. Designed host defense peptides (dHDPs) are synthetic analogues of naturally occurring HDPs, which provide defense against invading pathogens. This study investigates the use of novel dHDPs for the treatment of bacterial keratitis.\ud \ud Methods: The minimum inhibitory concentrations (MICs) were determined for dHDPs on both Gram-positive and -negative bacteria. The minimum biofilm eradication concentrations (MBEC) and in vitro time-kill assays were determined. The most active dHDP, RP444, was evaluated for propensity to induce drug resistance and therapeutic benefit in a murine Pseudomonas aeruginosa keratitis model.\ud \ud Results: Designed HDPs were bactericidal with MICs ranging from 2 to >64 μg/mL and MBEC ranging from 6 to 750 μg/mL. In time-kill assays, dHDPs were able to rapidly reduce bacterial counts upon contact with as little as 2 μg/mL. RP444 did not induce resistance after repeated exposure of P. aeruginosa to subinhibitory concentrations. RP444 demonstrated significant efficacy in a murine model of bacterial keratitis as evidenced by a significant dose-dependent decrease in ocular clinical scores, a significantly reduced bacterial load, and substantially decreased inflammatory cell infiltrates.\ud \ud Conclusions: Innovative dHDPs demonstrated potent antimicrobial activity, possess a limited potential for development of resistance, and reduced the severity of murine P. aeruginosa keratitis. These studies demonstrate that a novel dHDP may have potential to treat patients with sight-threatening bacterial keratitis.

Aspergillus flavus is an opportunistic, saprophytic fungus that infects maize and other fatty acid-rich food and feed crops and produces toxic and carcinogenic secondary metabolites known as aflatoxins. Contamination of maize with aflatoxin poses a serious threat to human health in addition to reducing the crop value leading to a substantial economic loss. Here we report designing a tachyplesin1-derived synthetic peptide AGM182 and testing its antifungal activity both in vitro and in planta. In vitro studies showed a five-fold increase in antifungal activity of AGM182 (vs. tachyplesin1) against A. flavus. Transgenic maize plants expressing AGM182 under maize Ubiquitin-1 promoter were produced through Agrobacterium-mediated transformation. PCR products confirmed integration of the AGM182 gene, while RT-PCR of maize RNA confirmed the presence of AGM182 transcripts. Maize kernel screening assay using a highly aflatoxigenic A. flavus strain (AF70) showed up to 72% reduction in fungal growth in the transgenic AGM182 seeds compared to isogenic negative control seeds. Reduced fungal growth in the AGM182 transgenic seeds resulted in a significant reduction in aflatoxin levels (76-98%). The results presented here show the power of computational and synthetic biology to rationally design and synthesize an antimicrobial peptide against A. flavus that is effective in reducing fungal growth and aflatoxin contamination in an economically important food and feed crop such as maize.

Md Shakir Uddin Ahmed,1 Ahmad Bin Salam,1 Clayton Yates,1 Kyle Willian,2 Jesse Jaynes,3 Timothy Turner,4 Mohamed O Abdalla5 1Department of Biology, Tuskegee University, Tuskegee, 2Department of Chemistry and Biochemistry, Auburn University, Auburn, 3Department of Environmental Sciences, Tuskegee University, Tuskegee, AL, 4Department of Biology, Jackson State University, Jackson, MS, 5Department of Chemistry, Tuskegee University, Tuskegee, AL, USA Abstract: As an alternative therapeutic treatment to reduce or eliminate the current side effects associated with advanced prostate cancer (PCa) chemotherapy, a multifunctional double-receptor-targeting iron oxide nanoparticles (IONPs) (luteinizing hormone-releasing hormone receptor [LHRH-R] peptide- and urokinase-type plasminogen activator receptor [uPAR] peptide-targeted iron oxide nanoparticles, LHRH-AE105-IONPs) drug delivery system was developed. Two tumor-targeting peptides guided this double-receptor-targeting nanoscale drug delivery system. These peptides targeted the LHRH-R and the uPAR on PCa cells. Dynamic light scattering showed an increase in the hydrodynamic size of the LHRH-AE105-IONPs in comparison to the non-targeted iron oxide nanoparticles (NT-IONPs). Surface analysis showed that there was a decrease in the zeta potential values for drug-loaded LHRH-AE105-IONPs compared to the NT-IONPs. Prussian blue staining demonstrated that the LHRH-AE105-IONPs were internalized efficiently by the human PCa cell line, PC-3. In vitro, magnetic resonance imaging (MRI) results confirmed the preferential binding and accumulation of LHRH-AE105-IONPs in PC-3 cells compared to normal prostate epithelial cells (RC77N/E). The results also showed that LHRH-AE105-IONPs significantly maintained T2 MRI contrast effects and reduced T2 values upon internalization by PC-3 cells. These paclitaxel-loaded double-receptor-targeting IONPs also showed an approximately twofold reduction in PC-3 cell viability compared to NT-IONPs. Keywords: LHRH-R, uPAR, prostate cancer, iron oxide nanoparticles, targeted drug delivery

Toxoplasma gondii is a ubiquitous intracellular zoonotic parasite estimated to affect about 30–90% of the world’s human population. The most affected are immunocompromised individuals such as HIV-AIDS and cancer patients, organ and tissue transplant recipients, and congenitally infected children. No effective and safe drugs and vaccines are available against all forms of the parasite. We report here the antagonistic and indifferent activity of the combination of five different formulations of pure synthetic 3-deoxyanthocyaninidin (3-DA) chloride compounds against T. gondii tachyzoites and the synergistic and additive interaction against a human foreskin fibroblast (HFF) cell line in vitro using fluorescence microscopy, trypan blue assay, and fractional inhibitory concentration index. The individual and the combined pure 3-DA compounds were observed to have effective inhibition against T. gondii parasites with less cytotoxic effect in a ratio of 1:1. The IC50 values for parasite inhibition ranged from 1.88 μg/mL (1.51–2.32 μg/mL) for luteolinindin plus 7-methoxyapigeninindin (LU/7-MAP) and 2.23 μg/mL (1.66–2.97 μg/mL) for apigeninindin plus 7-methoxyapigeninindin (AP/7-MAP) combinations at 95% confidence interval (CI) after 48 h of culture. We found LU/7-MAP to be antagonistic and AP/7-MAP to be indifferent in interaction against T. gondii growth. Both individual and combination 3-DA compounds not only depicted very strong inhibitory activity against T. gondii, but also had synergistic and additive cytotoxic effects against HFF cells. These synthetic 3-DAs have potential as antiparasitic agents for the treatment of human toxoplasmosis.

Acne vulgaris, caused by the Gram-positive bacterium Cutibacterium acnes, is a prevalent dermatologic condition with substantial cutaneous and psychological morbidity. Mild acne is treated with topical antibiotics with more severe inflammatory forms requiring the prolonged use of oral antibiotics, resulting in antimicrobial resistance development. Innovative treatment alternatives, providing complete microbicidal eradication with minimal safety issues and limited susceptibility to microbial resistance, are fervently sought. Designed antimicrobial peptides (dAMPs) are engineered analogs of naturally occurring AMPs that possess a reduced likelihood of developing bacterial resistance. Seven novel dAMP sequences were screened for in vitro bactericidal effectiveness against antibiotic resistant C. acnes clinical isolates. Five peptides (RP444, RP551, RP554, RP556, and RP557) exhibited potent in vitro antibacterial activity. The Therapeutic Index, a measure of specificity for killing multidrug resistant C. acnes over mammalian cells, was determined using bioluminescent human keratinocytes. The Therapeutic Index was highest for the disulfide dAMP, RP556, with a value of 130. The lead dAMP candidate RP556, was further evaluated in a multidrug-resistant C. acnes intradermal murine infection model. A topical application of 5 mg/mL RP556 (0.5%) eliminated infection. If these preclinical results are translated clinically, dAMPs may become a viable topical monotherapy for the treatment of recalcitrant acne infections.

Background: Prostate cancer (PCa) is higher among African American (AA) than Caucasian Americans (CA). AAs are more frequently diagnosed with PCa with worse prognoses than CAs. Support of a genetic component to the high incidence and mortality rate in AA men is based on epidemiologic studies of men with similar genetic backgrounds. For instance, men in Ghana and Nigeria also have a high incidence of prostate cancer, as do men of African descent in the Caribbean islands and in the United Kingdom. Multiple reports indicate that PCa aggressiveness is the result of cancer stem cells (CSC). Furthermore, people of African Ancestry have been reported to have increased stemness gene signature in multiple tumor types. CD133, which is a well-known progenitor/stem cells marker, and is associated with prostate tumor relapse and metastasize due to the existence of prostate cancer stem cells (PCaCSC) has been well characterized, however, its role in prostate cancer racial disparity is unknown. Therefore, our objective is to analyze the significance of CD133 as a disparity stem cell biomarker in AA and CA patients with late-stage PCa. Methods: TGCA Prostate Dataset was used for patient data. The R and R studio statistical software was used for the analysis, and for the survival analysis, Log-Rank test was used to determine survival. H & E was used to determine the presence of prostate cancer and tumors were scored using Gleason grading. CD133 protein location and expression was determined by IHC, and quantified using Aperio imaging software. Results: We analyzed genomic data in TGCA for correlation between CD133 over-expression and worst patient survival outcome. Survival analysis indicated a poorer survival outcome in the AA with high CD133 expression during late-stage PCa compare to the CA with the same stage of PCa. Furthermore, the addition of CD44 furthermore increased the significant difference between the stem cell population (p= 0.04) between AA and CA patients. To confirm these results, we evaluated CD133 expression in (Gleason =7) PCa tumor from AA and CA patients and compared them to BPH. As in the TCGA data, we observed increased CD133 expression in AA patients. Conclusion: Elevated CD133 shows an association with patients with African Ancestry. Further studies are necessary on a larger series of cases to elucidate the role of CD133 in the development and progression of prostate cancer and its suitability as a prognostic biomarker. Citation Format: Benjamin Adu-Addai, Ahmad B. Salam, Ruksana Amin, Honghe Wang, Huixian Lin, Anghesom Ghebremedhin, Jason White, Jesse M. Jaynes, Clayton Yates. CD133 as a disparity stem cell biomarker in African Americans with late-stage prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-181.

Background: Tumor associated M-ϕs (TAMs) have a complex etiology as a result of soluble factors secreted by prostate tumor cells, creating an immunosuppressive micro-environment (M-E) for the progression of late stage PC that has metastasized to the bone. The result is an M2-like polarization that expresses a number of M2-TAM specific markers, including CD206. Therapeutic targeting of TAMs has proven to be a challenge, due partly to a lack of understanding of the function of this biomarker and the bi-directional effects of TAMs on tumor cells. Our objective is to characterize the CD206 receptor in PC patients, and to test the potential of a novel engineered CD206 targeted peptide (T-P) to reverse the immune-suppressive M-Env in late stage PC. Methods: The TGCA Prostate Dataset was used for patient data and R software was used for informatics analysis. Small-angle X-ray scattering (SAXS) was used to generate the NMR structure of CD206. Peptide binding to the naïve CD206 receptor was determined in silico using PIPER, and was validated by Surface Plasmon Resonance (SPR). In vivo efficacy of CD206 T-P was determined in mice inoculated with PC-3 intratibially. Mice were treated with peptide alone, daily or twice a week at 10, 20, and 50mg/Kg, as a monotherapy or in combination with 20mg/Kg Docetaxel (DTX) over a 21day period. CD86 (M1) and CD206/CD163 (M2-TAM) markers and pro-inflammatory cytokines were determined by FACS. Bone osteolysis was determined by IHC of the entire bone, and bone turnover was determined by IHC analysis of RANKL. Results: TCGA data showed that over-expression of CD206 in Human PC is significantly associated with poor survival. In silico analyses showed the T-P exhibited strong affinity towards CD206 and was validated by SPR (Kd =3.57 µM). In bone-metastatic xenograft models of CRPC (PC-3), the flux differential of relative fluorescence in IVIS imaging showed peptide alone (at 20mg/kg qD sQ) decreased fluorescence by 64.36% compared with the untreated group. FACS analyses of M1/M2 markers CD86/CD206 in mice treated with peptide showed a 33.87 fold decrease in CD206 (M2-TAM) expression and a 7.6 fold increase in CD86 (M1-TAM) expression, compared with only a 4.4 fold decrease in CD206 expression and 0.44 fold decrease in CD86 expression in DTX treated mice. Stem cell marker CD133 showed a 4.7 fold decrease expression compared to the untreated group further suggesting that TAM repolarization reversed the immunosuppressive M-E. X-ray of tumors in bone suggests a reduction of osteolysis and was confirmed by IHC staining and analysis of whole bone showing fibrous and inflammatory remodeling patterns of tumor regression in the peptide only group. Conclusion: These results suggest that the novel engineered CD206 T-P repolarizes M2-TAM phenotype to M1-TAM which reverses the immunosuppressive cancer M-E in late stage PC. Citation Format: Ahmad B. Salam, Benjamin Adu-Addai, Huixian Lin, Anghesom Ghebremedhin, Jason White, Ruksana Amin, Balasubramanyam Karanam, George Martin, Charles Garvin, Henry Lopez, Jesse M. Jaynes, Clayton Yates. Novel synthetic peptide targets CD206 receptor promoting the repolarization of prostate cancer (PCa) TAMs and increase the efficacy of conventional prostate cancer therapeutic [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4062.

Two cultivars of Anthurium andraeanum Hort. hybrids, `Paradise Pink' and `Tropic Flame', were transformed by Agrobacterium to contain gene sequences for Shiva-1, a cecropin-based lytic peptide. The antibacterial gene was driven by a 35-35S cauliflower mosaic viral (35-35S CaMV) promoter and the construct included the secretory signal sequence for pathogenesis-related protein 1b (PR1b). Blight tolerance of regenerated plants was tested by inoculation with a virulent strain of Xanthomonas axonopodis (formerly campestris) pv. dieffenbachiae (Xad) that is bioluminescent to allow detection of symptomless infections in Shiva-1 transformants. Primary regenerants for two Shiva-1 transgenic lines of `Paradise Pink' displayed significantly enhanced tolerance to bacterial blight over blight susceptible `Rudolph' and even the blight tolerant `Kalapana'. Two Shiva-1 transgenic lines of `Tropic Flame' showed no improved resistance when compared to the control at the mean percent leaf infection level. One Shiva-1 transgenic line of `Tropic Flame' was unexpectedly more susceptible to blight than the nontransgenic control. Low expression of Shiva-1 observed in this line is hypothesized to be the cause of its increased susceptibility to Xad.

In order to increase the nutritional quality of cassava storage roots, which contain up to 85% starch of their dry weight, but are deficient in protein, a synthetic ASP1 gene encoding a storage protein rich in essential amino acids (80%) was introduced into embryogenic suspensions of cassava via Agrobacterium-mediated gene transfer. Transgenic plants were regenerated from suspension lines derived from hygromycin-resistant friable embryogenic callus lines. Molecular analysis showed the stable integration of asp1 in cassava genome and its expression at RNA level in transformed suspension lines. PCR and Southern analyses proved the transgenic nature of the regenerated plant lines. The expression of asp1 at RNA level was demonstrated by RT-PCR. The ASP1 tetramer could be detected in leaves as well as in primary roots of cultured transgenic plants by western blots. These results indicate that the nutritional improvement of cassava storage roots may be achieved by constitutive expression of asp1 in transgenic plants.

Introduction: Multiple reports have demonstrated that M2-polarized tumor associated macrophages (TAMs) play a significant role in promoting tumor metastasis, survival and resistance to chemotherapy. Thus, limiting the pro-tumorigenic activity of TAMs may hold great therapeutic promise. Objective: To determine whether targeting the Cluster of Differentiation 206 (CD206) receptor on TAMs with an engineered peptides having both CD206 specificity and apoptotic activity, will limit the protumorigenic effects of TAMs and enhance cancer cells response to chemotherapy. Method: A class of engineered peptides were designed to stimulate phagocytosis via the CD206 receptor, and to initiate apopotic cell death once endocytosed. Primary cells were isolated from C57BL/6J mice from Jackson Laboratory and were polarized to M1 and M2 phenotypes by treating with IL-4 (20ng/ml) and IFN-γ (10ng/ml) respectively from R&D Biosciences for 24 hrs. CD206 targeting peptide was biotin-labeled and utilized to treat M2-polarized cells. Precipitated proteins were analyzed by mass spectrometry analysis, and informatics software. In vitro proliferation and confirmation of apoptosis was assessed using Annexin/PI staining and Western blot analysis for Caspase 8 expression and activity. In xenograft models of triple negative breast cancer (MDA-MB-231), mice were treated with CD206 peptide and gemcitabine, singly or in combination Results: Mass spectrometry analysis of gel bands from the biotin / streptavidin pull down assay confirmed CD206 as a cell surface target. Bioinformatics analysis of the proteomics data from the pull down assay further confirmed that apoptotic proteins were highly expressed in the M2 populations than in the M1 populations. Treatment with CD206 peptide produced a significant decrease in cell proliferation only in M2 macrophages. FACS analysis of Annexin/PI staining and Caspase 8 activity, demonstrated by Western blot, showed that CD206 targeting peptide caused apoptosis specifically in M2 macrophages. In xenograft models of triple negative breast cancer (MDA-MB-231) mice treated with peptide alone (10 mg/kg qD subcu), there was a 39% reduction in tumor growth; gemcitabine @ 40 mg/kg q4D produced a 68% reduction; however, peptide in combination with gemcitabine completely blocked tumor growth. Moreover, immunohistochemistry staining of treated tumors showed a decrease in the expression of CD206 positive M2 macrophages and CD45/CD25 positive Treg cells, and an increase in CD86 positive M1 macrophages. These results were consistent with the in vitro results obtained. Discussion and Conclusion: These results suggest that a targeting CD206 peptide engineered to promote apoptosis, enhances the tumor response to chemotherapy by limiting the pro-tumorigenic activity of TAMs. Citation Format: Anghesom A. Ghebremedhin, Clayton Yates, Jesse Jaynes, George Martin, Henry Lopez, Charles Garvin. A novel peptide-suppressing M2 polarized tumor-associated macrophages enhances tumor response to chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1640. doi:10.1158/1538-7445.AM2017-1640

In the last several years, significant effort has been applied to identifying novel agents with effectiveness against prostate cancer. These studies were designed to determine the efficacy of one of these novel compounds, D2A21, in the treatment of an animal model of prostate cancer. Using the Mat-Ly-Lu(MLL) line of the Dunning R-3327 rat prostate adenocarcinoma model, the optimal dose, schedule and route of administration of D2A21 were established. A study involving the G line was used to further support these findings. In addition, hemotoxylin and eosin stained tissue samples were examined to investigate the extent of inhibition of lung metastases in animals injected with MLL cells. When D2A21 was injected intraperitoneally or subcutaneously, MLL and G cell tumor growth was inhibited 50-72% as demonstrated by both tumor volumes and weights. The optimal dosage of 0.179 mg/injection was established and it was determined to be most efficacious when administered five times per week. At this concentration, D2A21 appears to have no significant toxicity. Additionally, D2A21 increased the survival rate from only 25% to 70-75% in animals that were challenged with a large number of tumor cells. The peptide D2A21 is able to significantly inhibit tumor growth in rat models of prostate cancer. In addition, it can inhibit metastases and decrease deaths resulting from metastases in these animals.

The addition of an antimicrobial that can be synthesized by the mammalian immune system at the point of challenge may enhance disease resistance. A possible group of agents are cecropins, broad-spectrum antimicrobial peptides, which have been described and characterized. They are relatively non-toxic to normal cells from multicellular organisms but are toxic to a wide range of bacteria, protozoa and fungi, as well as infected and abnormal cells. Twenty-six lines of transgenic mice were produced by pronuclear injection of DNA consisting of the 5'-flanking region from -593 to +110 of the mouse interleukin 2 (IL-2) gene, Shiva 1a (a synthetic cecropinclass lytic peptide), and the SV40 polyadenylation/splice signal. A reverse-transcription PCR assay determined that two lines of transgenic mice were produced whose spleen-derived lymphocytes could be induced to transcribe and mature mRNA for Shiva 1a by exposure to 3.25 mg ml-1 of Con A. Two lines were challenged with an inoculation of 5 x 10(4) Brucella abortus strain 2308. After four weeks, there were significantly fewer B. abortus organisms in the spleens of transgenic mice than in non-transgenic control mice of the same strain (p < 0.05). Since the controlling regions of the IL-2 enhancer and the amino acid sequence of the signal peptide are highly conserved among several species, it is likely that this recombinant gene will function in other mammals.

Multiple lines of evidence suggest that macrophages, in particular M2-polarized tumor associated macrophages (TAMs), promote tumor aggressiveness and chemoresistance. Thus, limiting the pro-tumorigenic activity of TAMs may hold great therapeutic promise. To assess this potential, we synthesized artificial peptides (10-12mers) with a striapathic arrangement of hydrophobic and hydrophilic amino acids, designed to specifically target TAMs within the tumor microenvironment. These peptides, including drug candidate RP-182, are basic in design and bind to human albumin prior to binding to their eventual target, which enhances peptide half-life to around 2 hours. In vitro experiments demonstrated that exposure to 50uM peptide significantly reduced M2 macrophage viability and increased apoptosis after 48 hours of exposure, but had no effect on M1 macrophages. Interestingly, we did not observe a significant effect of RP-182 in vitro on various cancer cell lines, including MDA-MB-231, C42B or cells isolated from KPC960 mice. To determine whether RP-182 had in vivo efficacy we used multiple animal models, beginning with inflammatory indications where macrophage activity is also implicated, and progressing to solid organ cancer models: (1) In bleomycin animal models of lung and skin fibrosis, mice developed very high levels of inflammatory markers including IL6, which remained at control levels in mice treated with 10 mg/kg RP-182 qD subcu. At increased pulmonary bleomycin levels, all control animals died while 65% of treated animals survived. (2) In xenograft models of triple negative breast cancer (MDA-MB-231) mice treated with peptide (10 mg/kg qD subcu) demonstrated 37% reduction in MD-MB-231 tumor growth; gemcitabine @ 40 mg/kg q4D demonstrated 70% reduction; however, peptide plus gemcitabine completely blocked tumor growth. (3) In a xenograft model of castration resistant prostate cancer (CRPC) (C42B) mice treated with 2.5 mg/kg Docetaxel q7D demonstrated 45% reduction in tumor growth relative to control; mice treated with 10 mg/kg RP-182 qD demonstrated 52% reduction in tumor growth; but Docetaxel plus RP-182 reduced tumor growth 65%. (4) In the KPC960 model of pancreatic cancer, RP-182 treatment caused a 30% reduction in tumor growth and reduced the expression of a number of inflammatory genes in the tumors. (5) Finally, in the KRAS/p53 transgenic model of pancreatic cancer, treatment with peptide for one week reduced tumor growth, and was associated with 5.8 fold reduction in PDL1 and a 5.5 fold reduction in PDL2 expression in tumors. Toxicity testing on animals given much higher doses of RP-182 showed no changes in histology, blood counts, body or tissue weight. These results suggest that these novel designed peptides suppress macrophages in the tumors, enhancing the tumor response to chemotherapy and downregulating certain checkpoint proteins. This abstract is also presented as Poster B23. Citation Format: Henry Lopez, George R. Martin, Jesse M. Jaynes, Clayton Yates. Synthetic peptides suppress M2 macrophages and synergize with chemotherapy in prostate and breast cancer models. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr PR03.

Prostate Cancer (PCa) is the second leading cause of cancer-related deaths among men in the United States. Due to the harsh side effects of conventional chemo- and radiotherapies, targeted drug delivery is now gaining the focus of cancer researchers. The key for success of any newly developed targeted drug delivery systems is the novel design of targeting peptides which have high binding affinities to differentially over-expressed receptors on the surface of PCa cells. Two over-expressed such receptors, which can be targeted to the cell surface of PCa cells are: Gonadotropin Releasing Hormone Receptor (GnRH-R), and Prostate Specific Membrane Antigen (PSMA). The analysis done from molecular dynamics simulation data gave an important information about each interaction; such as RMSD, The number of contacts between receptor and peptide within a cutoff distance of 5 Å and the binding free energies, ΔGGBSA of the interactions. In all systems, the back bone RMSD deviation of the receptor was calculated using the last 10 ns of the sampling process and averaged over all trajectories. The RMSD data deviated between 1.22 - 2.51 Å. The free binding energies or ΔGGBSA was calculated from the last 10 ns of the sampling process. The QH1 system has the more negative ΔGGBSA -36.15 kcal mol-1 and the QH4 system has the least negative ΔGGBSA of -18.4 kcal mol-1 among the eight systems of GnRH-R. QH2 system exhibits a highly interactive hydrogen bond (bond distance is 2.65 Å) between 134th position of the receptor amino acid sequence GLU and 5th position of the qh2 peptide's TYR. The ΔGGBSA is for the qh2 system is – 34.92 kcal mol-1. In the PSMA and its targeting peptide interactions, T2IA has the least negative ΔGGBSA of -47.37 kcal mol-1. A salt bridge was observed between the 10th position of the T2IA peptide sequence ARG and the 328 position of the 3RBU receptor's GLU. Based on our molecular modeling studies, we have determined the best targeting peptides among all the newly designed peptides. The binding efficiency of the targeting peptides with the lowest binding energies will be further investigated surface plasmon resonance (SPR) in near future. Citation Format: Ahmad Salam, Vincent Hembrick, Jesse Jaynes, Timothy Turner, Mohamed Abdalla. Molecular modeling of novel peptide-receptor interaction for targeted drug delivery of prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2170.

An investigation was undertaken to determine the toxicity of an intravitreal injection of a novel peptide drug, Shiva-1, in rabbits. The drug, a synthetic peptide modeled after lytic peptides secreted by certain insects, has antiproliferative and antibacterial properties. Initial in vitro experiments showed that the drug, at a concentration of 100 microM, was toxic to both Y-79 retinoblastoma cells and human retinal pigment epithelial cells. A wide range of doses (6-1200 micrograms) was injected into the rabbit vitreous in an attempt to determine the maximum tolerated dose. Retinal toxicity was evaluated clinically, by electroretinography, and by light microscopy. Some localized toxicity was evident at 200 micrograms; all doses of 240 micrograms and above were toxic. While the drug appears to exhibit a narrow range between effective and toxic doses, the results suggest that this and other peptides of similar design merit further investigation for the treatment of proliferative and infectious diseases of the eye.

Preface 1. Immunomodulatory Cationic Peptide Therapeutics: A New Paradigm in Infection and Immunity Neeloffer Mookherjee, Leola N. Y. Chow, and Robert E. W. Hancock 2. Structure/Function Link Between Cytokine Domains and Natural and Designed Lytic Peptides: Medical Promise Jesse M. Jaynes and Gregory C. Bernard 3. The Potential of Frog Skin Antimicrobial Peptides for Development into Therapeutically Valuable Anti-Infective Agents J. M. Conlon 4. Obstacles and Solutions to the Use of Cationic Antimicrobial Peptides in the Treatment of Cancer Ashley L. Hilchie, Melanie R. Power Coombs, and David W. Hoskin 5. Lytic Peptides as Anticancer Therapeutics: Lessons Learned from a Novel Design Approach Clayton Yates, Timothy Turner, and Jesse M. Jaynes 6. Strategies for Designing Peptide Immunogens To Elicit ?-Helical Conformation-Specific Antibodies Reactive with Native Proteins Zhe Yan, Wendy J. Hartsock, Zhaohui Qian, Kathryn V. Holmes, and Robert S. Hodges 7. Defensins in Viral Infection Rachna Shah and Theresa L. Chang 8. "GENOPEP", a Topical Cream in the Treatment of Burn Wounds Jesse M. Jaynes and V. Siva Rami Reddy 9. Developing Influenza Antigen Microarrays for Seroprofiling Yu M. Foong and Mahesh Uttamchandani 10. pH-Directed Self-Assembling Helical Peptide Conformation J. Vincent Edwards, Alfred D. French, Thomas Jacks, and K. Rajasekaran 11. Controlling Symbiotic Microbes with Antimicrobial Peptides Peter Mergaert and Eva Kondorosi 12. Antimicrobial Peptides for Plant Disease Control. From Discovery to Application Emilio Montesinos, Esther Badosa, Jordi Cabrefiga, Marta Planas, Lidia Feliu, and Eduard Bardaji 13. Antimicrobial Peptides as a Promising Alternative for Plant Disease Protection B. Lopez-Garcia, B. San Segundo, and M. Coca 14. Strategies for Controlling Plant Diseases and Mycotoxin Contamination Using Antimicrobial Synthetic Peptides K. Rajasekaran, J. W. Cary, C. A. Chlan, J. M. Jaynes, and D. Bhatnagar 15. Antifungal Plant Defensins: Structure-Activity Relationships, Modes of Action, and Biotech Applications Uma Shankar Sagaram, Jagdeep Kaur, and Dilip Shah 16. Antifungal Peptides: Exploiting Non-Lytic Mechanisms and Cell Penetration Properties Jose F. Marcos, Monica Gandia, Eleonora Harries, Lourdes Carmona, and Alberto Munoz 17. Thionin Antifungal Peptide Synthesis in Transgenic Barley Jianming Fu, Minesh Patel, Anna Maria Nuutila, and Ron Skadsen 18. Expression of Designed Antimicrobial Peptides in Theobroma cacao L. Trees Reduces Leaf Necrosis Caused by Phytophthora spp. Luis C. Mejia, Mark J. Guiltinan, Zi Shi, Lena Landherr, and Siela N. Maximova 19. Antimicrobial Peptides for Fire Blight Control V. Sarojini 20. Thionins - Nature's Weapons of Mass Protection Svetlana Oard, Jong Hyun Ham, and Marc Alan Cohn 21. Transgenic Expression of Antimicrobial Peptides in Plants: Strategies for Enhanced Disease Resistance, Improved Productivity, and Production of Therapeutics Dmytro P. Yevtushenko and Santosh Misra Editors' Biographies Indexes

Angiogenesis plays a critical role in processes such as organ development, wound healing, and tumor growth. It requires well-orchestrated integration of soluble and matrix factors and timely recognition of such signals to regulate this process. Previous work has shown that newly forming vessels express the chemokine receptor CXC receptor 3 (CXCR3) and, activation by its ligand IP-10 (CXCL10), both inhibits development of new vasculature and causes regression of newly formed vessels. To identify and develop new therapeutic agents to limit or reverse pathological angiogenesis, we identified a 21 amino acid fragment of IP-10, spanning the α-helical domain residues 77–98, that mimic the actions of the whole IP-10 molecule on endothelial cells. Treatment of the endothelial cells with the 22 amino acid fragment referred to as IP-10p significantly inhibited VEGF-induced endothelial motility and tube formation in vitro, properties critical for angiogenesis. Using a Matrigel plug assay in vivo, we demonstrate that IP-10p both prevented vessel formation and induced involution of nascent vessels. CXCR3 neutralizing antibody was able to block the inhibitory effects of the IP-10p, demonstrating specificity of the peptide. Inhibition of endothelial function by IP-10p was similar to that described for IP-10, secondary to CXCR3-mediated increase in cAMP production, activation of PKA inhibiting cell migration, and inhibition of VEGF-mediated m-calpain activation. IP-10p provides a novel therapeutic agent that inhibits endothelial cell function thus, allowing for the modulation of angiogenesis.

Cecropin B is a naturally-occurring lytic peptide found in Hyalophora cecropia, the Giant Silk Moth. It is thought to comprise part of an inducible humoral defense system that combats infection in the insect. Two 38 amino acid peptides, SB-37 and Shiva-1, were produced as substitution analogs of Cecropin B. SB-37 is 95% homologous to Cecropin B while Shiva-1 retains only 46% homology to the natural molecule. However, hydrophobic properties and charge density of the native structure were conserved at 100% in the synthetic peptides. The genes for both peptides were chemically synthesized and cloned into the binary vector pBI121 under the control of a constitutive or wound-inducible plant promoter. Transgenic tobacco plants (RO) were subsequently obtained via Agrobacterium transformation. Bioassays to test disease resistance of R1 progeny indicate that, compared to transgenic control and SB-37 plants, Shiva-1 seedlings exhibited delayed wilt symptoms and reduced disease severity and mortality after infection with a highly virulent strain of Pseudomonas solanacearum. © 1993. Agricultural Experiment Station, New Mexico State University The authors wish to acknowledge the expert technical assistance in peptide synthesis and purification provided by Martha Juban. This research was supported, in part, by funds from the Louisiana State University Agricultural Experiment Station.

A chitobiase gene from Vibrio parahemolyticus was cloned into plasmid pUC18 in Escherichia coli strain DH5 alpha. The plasmid construct, pC120, contained a 6.4 kb Vibrio DNA insert. The recombinant gene expressed chitobiase [EC 3.2.1.30] activity similar to that found in the native Vibrio. The enzyme was purified by ion exchange, hydroxylapatite and gel permeation chromatographies, and exhibited an apparent molecular weight of 80 kDa on SDS-polyacrylamide gel electrophoresis. Chitobiose and 6 more substrates, including beta-N-acetyl galactosamine glycosides, were hydrolyzed by the recombinant chitobiase, indicating its putative classification as an hexosaminidase [EC 3.2.1.52]. The enzyme was resistant to denaturation by 2 M NaCl, thermostable at 45 degrees C and active over a very unusual (for glycosyl hydrolases) pH range, from 4 to 10. The purified cloned chitobiase gave 4 closely focussed bands on an isoelectric focusing gel, at pH 4 to 6.5. The N-terminal 43 amino acid sequence shows no homology with other proteins in commercial databanks or in the literature, and from its N-terminal sequence, appears to be a novel protein, unrelated in sequence to chitobiases from other Vibrios reported and unrelated to hexosaminidases from other organisms.

The lethal concentration of cecropin SB37 was determined for protoplasts from 11 plant cultivars or experimental lines representing 7 plant species and for 9 bacterial species that are pathogens of these plants. Lethal concentrations ranged from 4.5 μM for tomato ( Lycopersicon esculentum cv Red Cherry) to 41 μM for sugarbeet ( Beta vulgaris REL 1). Cecropin SB37 exhibited potent antibacterial activity against all of the bacterial pathogens tested. Lethal concentrations ranged from 0.1–4.5 μM. The difference between the lethal concentrations of cecropin SB37 for protoplasts from certain plants and their respective bacterial pathogens suggests it may be feasible to protect against these pathogens by introducing a modified cecropin gene into the plant.

Although oncoviruses and lentiviruses replicate by similar mechanisms, they differ fundamentally in the usual fate of the infected host cell during productive natural infections. Oncoviruses typically establish persistent nonlytic infections in natural host cells, while lentivirus infections characteristically result in a variety of cytopathic effects ultimately leading to death of the target cell. Described here is a unique structural motif consisting of a strongly amphipathic and arginine-rich helical peptide segment in the carboxyl end of lentivirus TM proteins that is structurally similar to the family of cytolytic peptides produced as defensive agents by certain insects and amphibians. Also demonstrated is the lytic nature of synthetic peptides constructed from the transmembrane (TM) protein of human and simian immunodeficiency viruses (HIV and SIV). Thus, it appears that the cytopathic properties of lentiviruses may be in part attributed to the presence of lytic peptides within the TM protein, designated lentivirus lytic peptide (LLP) and that variations in this segment could account for some of the differences observed in the cytopathicity among variants of a particular lentivirus.

Purpose: As an alternative to the drawbacks of current advanced prostate cancer chemotherapy, we propose a multifunctional double targeting drug delivery system that utilizes the combination of two cancer-targeting peptides: a modified luteinizing hormone releasing hormone (LHRH), the ligand for luteinizing hormone releasing hormone receptor (LHRH-R), and AE105, the ligand for urokinase type plasminogen activation receptor (uPAR). Both ligands are fused to amphiphilic polymer coated iron oxide nanoparticles (IONPs) and loaded with the anticancer drug Paclitaxel (PTX) as the payload. Materials and Methods: Targeted IONPs were characterized by both gel electrophoresis and dynamic light scattering (DLS). PTX was absorbed on the IONPs. Drug loading and release characteristics were conducted by HPLC. The binding specificity and the internalization efficiency of the targeted IONPs were both examined by Prussian blue staining and magnetic resonance imaging (MRI). Cytotoxicity of the targeted IONPs was evaluated by MTT assay. Results: Characterization of targeted IONPs by gel electrophoresis confirmed the successful attachment of the peptides to IONPs. Conjugation of peptides to carboxylic groups of polymer coating on IONPs resulted in an increase in the average hydrodynamic size of targeted IONPs (16.34 nm) as compared to non-targeted IONPs (12.51 nm), as well as a decrease of zeta potential from -70.43 mV to -58.06 mV, respectively. Prussian blue staining demonstrated that both, LHRH and AE105 conjugated IONPs were internalized efficiently by cells of the human prostate cancer cell line, PC3. In vitro MRI results showed that double-targeted IONPs significantly maintained T2 MRI contrast effect and reduction of T2 values upon internalization by PC3 cells. MRI imaging confirmed the preferential binding and accumulation of double-targeted IONPs in PC3 cells when compared to normal prostate epithelial cells (RC77N/E). PTX loaded double-targeted IONPs were stable at physiological pH and efficiently released around pH 4, the optimum pH inside the tumor cells. PTX loaded double-targeted IONPs showed an approximately 2-fold reduction in PC3 cell viability when compared to non-targeted IONPs. In addition, the percentage of cell death resulting from the PTX loaded, double-targeted IONPs was very similar to the percentage of cell death attributed to 100 ng/ml of free PTX, thereby demonstrating that their capability of reducing drug concentration. Conclusions: Our results indicate that we have developed a LHRH-R and uPAR targeted IONPs drug delivery system that potentially provides a MRI tractable delivery of cancer therapeutics such as PTX to prostate cancer cells. Therefore, our optimized double-targeted IONPs drug delivery system has the potential to significantly improve the health outcomes and quality of life for cancer patients as a novel type of targeted nanomedicine therapy. Citation Format: Md Shakir U. Ahmed, Mohamed O. Abdalla, Clayton Yates, Jesse Jaynes, Timothy Turner. Double receptor targeting multifunctional iron oxide nanoparticles drug delivery system for the treatment and imaging of prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3675. doi:10.1158/1538-7445.AM2015-3675

Purpose: Prostate Cancer (PCa) is the second leading cause of cancer-related deaths among men in the United States. Due to the harsh side effects of conventional chemo- and radio-therapies, targeted drug delivery is now gaining focus of cancer researchers. The key for success for any newly developed targeted drug delivery systems is the novel design of targeting peptides which have high binding affinities to differentially over-expressed receptors on the surface of PCa cells. Four over-expressed receptors which can be targeted on the cell surface of PCa cells are: (GnRH), (EGFR), (PSMA), and (uPAR). Thus, we propose to study the binding affinity of tweleve novel designed targeting peptides (three peptides per receptor) for these over-expressed receptors. Initially, we will study the binding affinity using a computerized molecular modeling program. We will corroborate our modeling data by determining the dissociation constants of the peptide-receptor interaction using sensitive experimental tools such as miscroscale thermophoresis. Methods: The newly designed peptides were generated in pdb (protein database) format and the known pdb files of the receptors were collected from protein data bank. Cluspro 2.0, developed by Boston University, is a protein docking server with a molecular modeling program that was used to calculate the binding energies of these peptides to their corresponding receptors. The data obtained was analyzed using Pymol. Results: The molecular docking studies showed that the GnRH tarteting peptide QH10, uPAR targeting peptide CV13, EGFR targeting peptide RL10, and PSMA targeting peptide TH12 have the lowest mean binding energies for their respective top three binding conformations. The calculatd binding energies for the aftermentioed peptides-receptors combination are: -1285 KCal/M, -1029 KCal/M, -1019 KCal/M and -1037 KCal/M, respectively. There results suggested a very high interaction for these newly designed peptides and their corroponding receptors as the typical calculated binding energy for an antigen-antibody interaction is -700 KCal/M. Conclusion: Based on our molecular docking studies, we have determined the best targeting peptides among all the newly desiged peptides. The binding efficiency of the targeting peptides with the lowest binding energies will be further investigated using microscale thermophoresis. This work is supported by grant funding from NIH/RCMI G12MD00758 (T. Turner) and NIH/NCI U54 CA118623 (T. Turner & M. Abdalla). Note: This abstract was not presented at the meeting. Citation Format: Mohamed O. Abdalla, Ahmad Bin Salam, Vincent Hembrick, Manikanthan Bhavaraju, Clayton Yates, Jesse Jaynes, Timothy Turner. Molecular modeling studies of novel receptor targeted peptides in the treatment of prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3694. doi:10.1158/1538-7445.AM2015-3694

Fertile, transgenic cotton plants expressing the synthetic antimicrobial peptide, D4E1, were produced through Agrobacterium-mediated transformation. PCR products and Southern blots confirmed integration of the D4E1 gene, while RT-PCR of cotton RNA confirmed the presence of D4E1 transcripts. In vitro assays with crude leaf protein extracts from T0 and T1 plants confirmed that D4E1 was expressed at sufficient levels to inhibit the growth of Fusarium verticillioides and Verticillium dahliae compared to extracts from negative control plants transformed with pBI-d35S(Omega)-uidA-nos (CGUS). Although in vitro assays did not show control of pre-germinated spores of Aspergillus flavus, bioassays with cotton seeds in situ or in planta, inoculated with a GFP-expressing A. flavus, indicated that the transgenic cotton seeds inhibited extensive colonization and spread by the fungus in cotyledons and seed coats. In planta assays with the fungal pathogen, Thielaviopsis basicola, which causes black root rot in cotton, showed typical symptoms such as black discoloration and constriction on hypocotyls, reduced branching of roots in CGUS negative control T1 seedlings, while transgenic T1 seedlings showed a significant reduction in disease symptoms and increased seedling fresh weight, demonstrating tolerance to the fungal pathogen. Significant advantages of synthetic peptides in developing transgenic crop plants that are resistant to diseases and mycotoxin-causing fungal pathogens are highlighted in this report.

In order to increase the nutritional quality of cassava storage roots, which contain up to 85% starch of their dry weight, but are deficient in protein, a synthetic ASP1 gene encoding a storage protein rich in essential amino acids (80%) was introduced into embryogenic suspensions of cassava via Agrobacterium-mediated gene transfer. Transgenic plants were regenerated from suspension lines derived from hygromycin-resistant friable embryogenic callus lines. Molecular analysis showed the stable integration of asp1 in cassava genome and its expression at RNA level in transformed suspension lines. PCR and Southern analyses proved the transgenic nature of the regenerated plant lines. The expression of asp1 at RNA level was demonstrated by RT-PCR. The ASP1 tetramer could be detected in leaves as well as in primary roots of cultured transgenic plants by western blots. These results indicate that the nutritional improvement of cassava storage roots may be achieved by constitutive expression of asp1 in transgenic plants.

Cassava (Manihot esculenta Crantz) is a staple food of more than 500 million people in the tropics. Its storage roots contain starch up to 85% of their dry weight, but are deficient in protein. People depending heavily on cassava may consequently suffer from qualitative malnutrition, unless they can supplement their diet with protein from other sources. Traditional breeding of cassava is difficult due to irregular flowering and low fertility as well as to low seed set and germination rates of the plants, and attempts to improve the protein content of cassava roots have so far been unsuccessful. Advances in plant genetic engineering now provide an alternative to traditional breeding in improving cassava, such as improved root quality and disease resistance.