Transgenic Cre expression mice for generation of erythroid-specific gene alterations

Transgenic mice that express Cre recombinase in erythroid cell lineages were developed so that genes affecting erythropoiesis/hematopoiesis may be altered without necessarily affecting fetus viability. A micro-LCR cassette-beta-globin promoter-Cre recombinase gene (microLCR-betapr-Cre) construct was synthesized and used to generate transgenic mice. Concurrently, we produced mice containing a microLCR-loxP-flanked beta sickle gene (microLCR-loxP-beta(S)-loxP) construct. microLCR-betapr-Cre mice with intact transgenes in variable copy number were identified. Cre expression was assessed by RNAse protection and RT-PCR. Cre function was ascertained by breeding to microLCR-loxP-beta(S)-loxP mice. We demonstrate that beta(S) expression was not detected in the blood of bigenics, but the gene was present in nonerythroid cells. Thus, excision of the loxP-flanked beta(S) gene was restricted to erythroid cell lineages.     

Bionomics and morphological and molecular characterization of Elasmus schmitti and Baryscapus elasmi (Hymenoptera: Chalcidoidea, Eulophidae), parasitoids associated with a paper wasp, Polistes dominulus (Vespoidea, Vespidae)

Elasmus schmitti and Baryscapus elasmi have been recorded in southern Ukraine as gregarious parasitoids in the nests of the paper wasps Polistes dominulus and Polistes nimphus. Polistes dominulus nests infested with E. schmitti were less productive than uninfested nests in only one year (2004) of the three years of the present study, when an increase in the host population size occurred. Females of E. schmitti are synovigenic, and they lay their eggs on the skins of P. dominulus last instar larvae, without paralyzing the host. Rather, the parasitoid larvae feed on young host pupae. The pupae of E. schmitti are isolated from the host remnants by a thin fecal partition as in Elasmus polistis and Elasmus japonicus, other paper wasp parasitoids. Baryscapus elasmi is a pupal endoparasitoid of E. schmitti. The females of B. elasmi emerge without mature eggs in their ovaries and mate with males. They penetrate the paper wasp’s cells with their ovipositor and feed on the extracted hemolymph exudate. Pupation of B. elasmi occurs inside or outside the pupa of the host, E. schmitti. If inside, then the cranial end of the pupa and the adult emergence hole of B. elasmi are situated in the caudal ends of the pupae of their hosts. Comparative notes and illustrations on the morphology of adults are provided, and DNA sequences of three genes (nuclear 28S D2 rDNA, mitochondrial cytochrome oxidase subunit I, and mitochondrial cytochrome b) were obtained for both parasitoid species. The similarity of the 28S D2 sequences of E. schmitti and E. polistis relative to other available Elasmus sequences suggests a single origin of parasitism on paper wasps in this genus.     

PHEX Mimetic (SPR4-Peptide) Corrects and Improves HYP and Wild Type Mice Energy-Metabolism

Context

PHEX or DMP1 mutations cause hypophosphatemic-rickets and altered energy metabolism. PHEX binds to DMP1-ASARM-motif to form a complex with α₅β₃ integrin that suppresses FGF23 expression. ASARM-peptides increase FGF23 by disrupting the PHEX-DMP1-Integrin complex. We used a 4.2 kDa peptide (SPR4) that binds to ASARM-peptide/motif to study the DMP1-PHEX interaction and to assess SPR4 for the treatment of energy metabolism defects in HYP and potentially other bone-mineral disorders.

Design

Subcutaneously transplanted osmotic pumps were used to infuse SPR4-peptide or vehicle (VE) into wild-type mice (WT) and HYP-mice (PHEX mutation) for 4 weeks.

Results

SPR4 partially corrected HYP mice hypophosphatemia and increased serum 1.25(OH)₂D₃. Serum FGF23 remained high and PTH was unaffected. WT-SPR4 mice developed hypophosphatemia and hypercalcemia with increased PTH, FGF23 and 1.25(OH)₂D₃. SPR4 increased GAPDH HYP-bone expression 60× and corrected HYP-mice hyperglycemia and hypoinsulinemia. HYP-VE serum uric-acid (UA) levels were reduced and SPR4 infusion suppressed UA levels in WT-mice but not HYP-mice. SPR4 altered leptin, adiponectin, and sympathetic-tone and increased the fat mass/weight ratio for HYP and WT mice. Expression of perlipin-2 a gene involved in obesity was reduced in HYP-VE and WT-SPR4 mice but increased in HYP-SPR4 mice. Also, increased expression of two genes that inhibit insulin-signaling, ENPP1 and ESP, occurred with HYP-VE mice. In contrast, SPR4 reduced expression of both ENPP1 and ESP in WT mice and suppressed ENPP1 in HYP mice. Increased expression of FAM20C and sclerostin occurred with HYP-VE mice. SPR4 suppressed expression of FAM20C and sclerostin in HYP and WT mice.

Conclusions

ASARM peptides and motifs are physiological substrates for PHEX and modulate osteocyte PHEX-DMP1-α₅β₃-integrin interactions and thereby FGF23 expression. These interactions also provide a nexus that regulates bone and energy metabolism. SPR4 suppression of sclerostin and/or sequestration of ASARM-peptides improves energy metabolism and may have utility for treating familial rickets, osteoporosis, obesity and diabetes.     

Differential effects of age on circulating and splenic leukocyte populations in C57BL/6 and BALB/c male mice

Background  

Despite several reports on age-related phenotypic changes of the immune system's cells, studies that use a multipoint age comparison between the specific and innate immune cell populations of prototypical Th1- and Th2-type polarized mouse strains are still lacking.