Development of N-Terminally Modified Variants of the CXCR4-Antagonistic Peptide EPI-X4 for Enhanced Plasma Stability.

EPI-X4, a natural peptide CXCR4 antagonist, shows potential for treating inflammation and cancer, but its short plasma stability limits its clinical application. We aimed to improve the plasma stability of EPI-X4 analogues without compromising CXCR4 antagonism. Our findings revealed that only the peptide N-terminus is prone to degradation. Consequently, incorporating d-amino acids or acetyl groups in this region enhanced peptide stability in plasma. Notably, EPI-X4 leads 5, 27, and 28 not only retained their CXCR4 binding and antagonism but also remained stable in plasma for over 8 h. Molecular dynamic simulations showed that these modified analogues bind similarly to CXCR4 as the original peptide. To further increase their systemic half-lives, we conjugated these stabilized analogues with large polymers and albumin binders. These advances highlight the potential of the optimized EPI-X4 analogues as promising CXCR4-targeted therapeutics and set the stage for more detailed preclinical assessments.

An optimized derivative of an endogenous CXCR4 antagonist prevents atopic dermatitis and airway inflammation.

Aberrant CXCR4/CXCL12 signaling is involved in many pathophysiological processes such as cancer and inflammatory diseases. A natural fragment of serum albumin, named EPI-X4, has previously been identified as endogenous peptide antagonist and inverse agonist of CXCR4 and is a promising compound for the development of improved analogues for the therapy of CXCR4-associated diseases. To generate optimized EPI-X4 derivatives we here performed molecular docking analysis to identify key interaction motifs of EPI-X4/CXCR4. Subsequent rational drug design allowed to increase the anti-CXCR4 activity of EPI-X4. The EPI-X4 derivative JM#21 bound CXCR4 and suppressed CXCR4-tropic HIV-1 infection more efficiently than the clinically approved small molecule CXCR4 antagonist AMD3100. EPI-X4 JM#21 did not exert toxic effects in zebrafish embryos and suppressed allergen-induced infiltration of eosinophils and other immune cells into the airways of animals in an asthma mouse model. Moreover, topical administration of the optimized EPI-X4 derivative efficiently prevented inflammation of the skin in a mouse model of atopic dermatitis. Thus, rationally designed EPI-X4 JM#21 is a novel potent antagonist of CXCR4 and the first CXCR4 inhibitor with therapeutic efficacy in atopic dermatitis. Further clinical development of this new class of CXCR4 antagonists for the therapy of atopic dermatitis, asthma and other CXCR4-associated diseases is highly warranted.

Hit evaluation of an α-helical peptide: Ala-scan, truncation and sidechain-to-sidechain macrocyclization of an RNA polymerase Inhibitor.

RNA polymerase (RNAP) remains a relatively underexplored target with only rifampicin and fidaxomicin in clinical use. Hence, the concurrent rise in bacterial resistance rate urges the search for novel RNAP inhibitors with a novel mode of action. In this work, we investigated the impact of several systematic modifications including sidechain-to-sidechain macrocylization in the α-helical content and biological activity of a previously identified inhibitory sigma factor fragment. Ala-scan results, peptide truncation from both the N- and C-terminus and modifications inspired by other RNAP inhibitors revealed novel structure activity relationships but did not yield a superior sequence. Additionally, four insertion points for non-natural amino acids bearing side chains required for macrocylization were explored. Linear precursors showed improved stabilization of the α-helical content compared to the original sequence as demonstrated by circular dichroism (CD) spectroscopy. However, this increase in α-helicity did not translate into improved biological activity. Instead, complete abolishment of RNAP inhibitory activity occurred. We hypothesize three possible reasons for such a discrepancy and offer the basis for further optimization efforts for this peptidic RNAP inhibitor.

Comparison Between Handgrip Dynamometry and Manual Muscle Testing Performed by Registered Dietitians in Measuring Muscle Strength and Function of Hospitalized Patients.

BACKGROUND: The Academy of Nutrition and Dietetics and American Society the Parenteral and Enteral Nutrition (ASPEN) Consensus Statement recommends a standardized set of diagnostic characteristics to identify adult malnutrition. Due to lack of a consensus definition and challenges with measurements, physical function or performance has traditionally been difficult to assess. The purpose of this study was to determine whether manual muscle testing (MMT) performed by registered dietitians (RDs) can be used as a surrogate measurement of muscle strength and function in hospitalized patients. METHOD: Patients admitted to the heart failure service on the cardiac stepdown units at the Cleveland Clinic Main Campus in Cleveland, Ohio, were eligible for the study, and those who met the inclusion criteria underwent handgrip strength (HGS) testing and evaluation of nutrition status using the Academy/ASPEN Characteristics Recommended for the Identification of Adult Malnutrition. MMT was then performed within 24 hours by a different study investigator blinded to the HGS and malnutrition assessment results. RESULTS: It was found that HGS and MMT overall were in agreement for 84% of patients and that MMT had a high sensitivity (98%) but low specificity (13%). CONCLUSION: This study shows feasibility for RDs to perform MMT on patients to determine muscle strength and functioning. Future practice application may be to incorporate MMT into screening criteria for patients being evaluated for malnutrition and reserve HGS testing only for patients with an abnormal MMT.

Design and Synthesis of Novel Phenylpiperazine Derivatives as Potential Anticonvulsant Agents.

Eighteen new 5-benzylidene-3-(4-arylpiperazin-1-ylmethyl)-2-thioxo-imidazolidin-4-ones were designed as hybrid structures from previously reported anticonvulsant compounds, synthesized and tested for anticonvulsant activity. Initial anticonvulsant screening was performed using the strychnine (2 mg/kg IP) potent generalized-induced seizure and pentylenetetrazole (PTZ) (60 mg/kg IP) acute clonic-induced convulsion screens in mice. All the molecules were found to be effective in at least one seizure model, compounds 10, 13, 15, 17, and 18 were active against both types of seizures induced. Compound 13 turned out to be the most active candidate within the strychnine model, having an average survival time of 6 min close to that of the positive control phenytoin, while compound 8 showed 100% protection from the induced PTZ seizures, resembling the protection of the positive control phenobarbital. Initial SAR studies for anticonvulsant activity are discussed.

The association between home parenteral nutrition and patients with FAP-associated intra-abdominal desmoids: a retrospective study.

BACKGROUND: Intra-abdominal desmoid tumors (IADTs) are a common complication of familial adenomatous polyposis (FAP). Treatment is not standardized for advanced disease. Medical and surgical treatments may be ineffective in preventing complications, which can cause intestinal failure. Home parenteral nutrition (HPN) can be a life-saving treatment in these patients. The aim of this study was to investigate the association with HPN in FAP-IADTs. METHODS: A retrospective review of FAP patients with IADTs at the Cleveland Clinic (CC) between 1980 and 2009 was performed. Patients and tumor characteristics were retrieved from the CC Jagelman Registry for Inherited Neoplasms and CC HPN database. Inclusion criteria were FAP-IADTs and 6-month follow up at CC. Exclusion criteria were <6-month follow-up, lack of 3-dimensional lesion or sheet desmoid, and/or incomplete medical records. Kaplan-Meier curves were analyzed for HPN and non-HPN groups. RESULTS: One hundred fifty-four patients were included and divided into 2 groups: HPN (n = 41, 26.6%) and non-HPN (n = 113, 73.4%). The HPN group was more likely to have advanced-stage disease and significantly higher incidence of chronic abdominal pain, narcotic dependency, bowel obstruction, ureteral obstruction, deep vein thrombosis, pulmonary embolism, fistulae, and sepsis (P < .05). The need for HPN represented a strong predictor of mortality (5-year survival HPN = 72% vs non-HPN = 95%), but duration of HPN did not affect mortality. CONCLUSION: HPN, although a life-saving treatment, is an independent poor prognostic factor associated with high morbidity and mortality.