Chronic preclinical safety evaluation of EPO-018B, a pegylated peptidic erythropoiesis-stimulating agent in monkeys and rats.

EPO-018B, a synthetic peptide-based erythropoiesis stimulating agent (ESA), is mainly designed for treatment of anemia caused by chronic renal failure and chemotherapy against cancer. It overcomes the deficiencies of currently approved ESA, including the frequent administration of temperature-sensitive recombinant protein and anti-EPO antibody-mediated pure red cell aplasia (PRCA). This study was designed to evaluate the potential chronic toxicity of EPO-018B. Subcutaneous administration doses were designed as 0, 0.2, 1 and 10mg/kg for six months for 160 rats (20/gender/group) and 0, 0.3, 3 and 20mg/kg for nine months for 32 monkeys (4/gender/group) once every three weeks. The vehicles received the same volume of physiological saline injection. All animals survived to the scheduled necropsies after six weeks (for rats) and fourteen weeks (for monkeys) recovery period, except for the two high-dose female rats and two high-dose male monkeys, which were considered related to the increased RBCs, chronic blood hyperviscosity and chronic cardiac injury. EPO-018B is supposed to be subcutaneously injected once every month and the intended human therapeutic dose is 0.025mg/kg. The study findings at 0.2mg/kg for rats and 0.3mg/kg for monkeys were considered to be the study NOAEL (the no observed adverse effect level), which were more than ten times the intended human therapeutic dose. Higher doses caused adverse effects related to the liver toxicity, cardiotoxicity, appearance of neutralizing antibodies of EPO-018B and the decrease of serum glucose and cholesterol. Most treatment-induced effects were reversible or revealed ongoing recovery upon the discontinuation of treatment. The sequelae occurred in rats and monkeys were considered secondary to exaggerated pharmacology and would less likely occur in the intended patient population. As to the differences between human beings and animals, the safety of EPO-018B need to be further confirmed in the future clinical studies.

Subchronic safety evaluation of CMS-1 (a botanical antihypertensive product derived from Semen Cnidium monnieri) in Sprague-Dawley rats and beagle dogs.

CMS-1, mainly composed of imperatorin as its active compound, is a partially purified fraction of a Chinese herbal medicine, Semen Cnidium monnieri. CMS-1 has the potential to be further developed as a new treatment for hypertension. Thus, we studied its toxicity in both Sprague-Dawley rats and beagle dogs. Rats (0-900mg/kg/day) and dogs (0-450mg/kg/day) received CMS-1 orally for 30 consecutive days, followed by a 15-day recovery period. The major target organs of CMS-1 toxicity are the GI (inappetence), liver (hepatocellular necrosis, enzyme elevation), thymus (atrophy), cardiovascular (hypotension), changes in ECG T and P waveforms, elevation of nitrous oxide levels and hematological (RBC parameters disturbances) systems. Most treatment-induced adverse effects were reversible or showed a progressive recovery upon discontinuation of the treatment. The No Observed Adverse Effect Level (NOAEL) was 100mg/kg/day for rats and 50mg/kg/day for dogs. This non-clinical study suggests that clinical monitoring of CMS-1 in patients should focus on the gastrointestinal system, blood tests for liver functions, electrolytes, and blood homeostasis, cardiovascular functions, and immune functions.

Identification of a functional nuclear localization signal mediating nuclear import of the zinc finger transcription factor ZNF24.

ZNF24 is a member of the SCAN domain family of Krüppel-like zinc finger (ZF) transcription factors, which plays a critical role in cell proliferation and differentiation. However, how ZNF24 enters the nucleus in order to exert its function remains unclear since its nuclear localization signal(s) (NLS) has not been identified. Here, we generated a series of GFP-tagged deletion and point mutants and assessed their subcellular localization. Our results delimit the NLS to ZF1-2. Deletion of ZF1-2 caused cytoplasmic accumulation of ZNF24. Fusion of the ZF1-2 to green fluorescent protein (GFP) targeted GFP to the nucleus, demonstrating that the ZF1-2 is both necessary and sufficient for nuclear localization. ZNF24 containing histidine to leucine mutations that disrupt the structure of ZF1 or/and ZF2 retains appropriate nuclear localization, indicating that neither the tertiary structure of the zinc fingers nor specific DNA binding are necessary for nuclear localization. K286A and R290A mutation led to partial cytoplasmic accumulation. Co-immunoprecipitation demonstrated that ZNF24 interacted with importin-ß and this interaction required the ZF motifs. The ß-Catenin (CTNNB1) luciferase assays showed that the ZNF24 mutants defective in nuclear localization could not promote CTNNB1 promoter activation as the wild-type ZNF24 did. Taken together, these results suggest that consecutive ZF1-2 is critical for the regulation of ZNF24 nuclear localization and its transactivation function.

Subchronic safety evaluation of EPO-018B, a pegylated peptidic erythropoiesis stimulating agent, after 5-week subcutaneous injection in Cynomolgus monkeys and Sprague-Dawley rats.

EPO-018B, a synthetic peptide-based erythropoiesis stimulating agent (ESA), is coupled to polyethylene glycol (PEG) and designed to specifically bind and activate the erythropoietin (EPO) receptor to result in production of red blood cells. This study was designed to evaluate the potential subchronic toxicity of EPO-018B for Cynomolgus monkeys and Sprague-Dawley rats both at 0, 0.5, 5 and 50 mg/kg every week for 5 weeks, followed by 6-week recovery for rats and 12-week recovery for monkeys. The No Observed Adverse Effect Level (NOAEL) for rats and monkeys were both considered to be at least 0.5 mg/kg/day, the minimum toxic dose to be 5.0 mg/kg/day and the severe toxic dose to be more than 50.0 mg/kg/day. The toxicological effects included the exaggerated pharmacology and secondary sequelae that resulted from an erythropoiesis-stimulating agent treatment to healthy animals. Most treatment induced effects were reversible or showed ongoing recovery upon discontinuation of treatment. The anticipated patient population for EPO-018B treatment is targeted to be the anemia patients caused by chronic renal failure or chemotherapy against to cancer and is expected to have an ideal clinical application prospect.

Mimic peptides bonding specifically with the first and second extracellular loops of the CC chemokine receptor 5 derived from a phage display peptide library are potent inhibitors of experimental autoimmune encephalomyelitis.

PURPOSE: To obtain mimic peptides that specifically bind with the first and second extracellular loops (ECL1, ECL2) of the CC chemokine receptor 5 (CCR5) and to study their treatment effects on experimental autoimmune encephalomyelitis (EAE) mice. METHODS: A phage display peptide library was applied to screen peptides that bond with ECL1 and ECL2. ELISA and DNA sequence analysis were used to identify positive clones. EAE mice were treated with synthesized peptides by intraperitoneal injection. RESULTS: Eighteen positive clones were obtained and four peptides with sequences STFTTTL, TPIPQLL, SLPLPKP and QTSSAAL were identified. These peptides could significantly protect against and reduce the severity of EAE. The infiltration of monocytes and lymphocytes into the spinal cord decreased significantly in treated mice, while abundant inflammatory cells and demyelination were observed in spinal cords of EAE mice. CONCLUSION: CCR5 mimic peptides provided a significant protective effect to EAE mice. These potent inhibitory mimic peptides could be useful in the clinical treatment of multiple sclerosis.

Directed neural differentiation of duck embryonic germ cells.

Although the avian primordial germ cells (PGCs) have been used to produce transgenic birds, their characteristics largely remain unknown. The isolation, culture, biological characterization, and directed neural differentiation of duck EG cells were assayed in this study. The Results showed that the EG cells were got by isolating embryonic gonad and surrounding tissue from 7-day-old duck embryo. The PGCs co-cultured with their gonadal somatic cells were well grown. After passaging, the EG cells were incubated in medium with cytokines and Mitomycin C on inactivated duck embryonic fibroblasts (DEFs) feeder layers. After several passages, alkaline phosphatase (ALP) and periodic acid-Schiff (PAS) resulted positive, cellular markers detection positive for SSEA-1, SSEA-4, TRA-1-60, and TRA-1-81. Karyotype analysis showed the EG cells kept diploid condition and the hereditary feature was stable in accordance with varietal characteristics of duck. These cells grew continuously for 11 passages on DEFs. Under induction of medium with BME, RA, and IBMX, the EG cells lost undifferentiated state, large amount of neural cells appeared with the formation of neural cells networks. Special Nissl body was found by toluidine blue stain after induced for 7 days. Immunofluorescence staining results indicated that differentiated EG cells expressed Nestin, NSE, and GFAP positive. The expression of Nestin, NSE, and GFAP mRNA were positive by RT-PCR. The results revealed that RA can obviously promote the directed differentiation of duck EG cells into neural lineage. The duck EG cells will be useful for the production of transgenic birds, for cell replacement therapy and for studies of germ cell differentiation.

Establishment of transgenic mice carrying gene encoding human zinc finger protein 191.

AIM: Human zinc finger protein 191 (ZNF191) was cloned and characterized as a Kruppel-like transcription factor, which might be relevant to many diseases such as liver cancer, neuropsychiatric and cardiovascular diseases. Although progress has been made recently, the biological function of ZNF191 remains largely unidentified. The aim of this study was to establish a ZNF 191 transgenic mouse model, which would promote the functional study of ZNF191. METHODS: Transgene fragments were microinjected into fertilized eggs of mice. The manipulated embryos were transferred into the oviducts of pseudo-pregnant female mice. The offsprings were identified by PCR and Southern blot analysis. ZNF 191 gene expression was analyzed by RT-PCR. Transgenic founder mice were used to establish transgenic mouse lineages. The first generation (F1) and the second generation (F2) mice were identified by PCR analysis. Ten-week transgenic mice were used for pathological examination. RESULTS: Four mice were identified as carrying copies of ZNF191 gene. The results of RT-PCR showed that ZNF 191 gene was expressed in the liver, testis and brain in one of the transgenic mouse lineages. Genetic analysis of transgenic mice demonstrated that ZNF 191 gene was integrated into the chromosome at a single site and could be transmitted stably. Pathological analysis showed that the expression of ZNF 191 did not cause obvious pathological changes in multiple tissues of transgenic mice. CONCLUSION: ZNF 191 transgenic mouse model would facilitate the investigation of biological functions of ZNF191 in vivo.