Sclerostin-Neutralizing Antibody Treatment Rescues Negative Effects of Rosiglitazone on Mouse Bone Parameters

Obesity, a growing pandemic, is a risk factor for many cancers and causes increased bone marrow adipose tissue (BMAT). in vitro studies and obese animal models suggest that BMAT contributes to cancer progression, but there is a lack of preclinical models to directly test BMAT's role in cancer. Overactivation of peroxisome-proliferator-activated receptor-γ (PPARγ) can skew bone formation and resorption rates, resulting in increased BMAT and trabecular bone loss. Thiazolidinediones (eg, rosiglitazone) are anti-diabetic therapies that promote adipogenesis through PPARγ activation. We investigated if rosiglitazone increases BMAT in an immunocompromised model, commonly used in cancer research, and if these effects could be reversed by co-administering a bone anabolic agent (sclerostin-neutralizing antibody [Scl-Ab]), which has been shown to inhibit adipogenesis, using DXA, μCT, OsO4 μCT, and dynamic histomorphometry. Four weeks of rosiglitazone in female SCID Beige mice (cohort 1) significantly decreased trabecular bone volume (BV/TV) by about one-half, through increased osteoclast and suppressed osteoblast activity, and significantly increased BMAT. In cohort 2, mice were administered rosiglitazone ± Scl-Ab for 4 weeks, and then rosiglitazone was discontinued and Scl-Ab or vehicle were continued for 6 weeks. Scl-Ab significantly increased bone parameters (eg, BV/TV, N.Ob/B.Pm, and MS/BS) in both groups. Scl-Ab also overcame many negative effects of rosiglitazone (eg, effects on trabecular bone parameters, increased mineralization lag time [MLT], and decreased bone formation rate [BFR]). Interestingly, Scl-Ab significantly decreased rosiglitazone-induced BMAT in the femur, mostly due to a reduction in adipocyte size, but had a much weaker effect on tibial BMAT. These data suggest targeting sclerostin can prevent rosiglitazone-induced bone loss and reduce BM adiposity, in some, but not all BMAT locations. Collectively, our data demonstrate that rosiglitazone increases BMAT in SCID Beige mice, but concomitant changes in bone may confound its use to specifically determine BMAT's role in tumor models. © 2020 American Society for Bone and Mineral Research (ASBMR).     

Clinical and genetic features of variegate porphyria in a Chinese patient

Acute porphyria is rare in orientals. We describe a Chinese woman with recurrent generalised tonic-clonic seizures and abdominal pain. Genomic DNA studies identified a heterozygous base substitution from guanine to adenine at nucleotide position 503, resulting in substitution of arginine by histidine at position 168 of the protein (R168H). This genetic abnormality is similar to the mutation reported in Caucasians with variegate porphyria. To the best of our knowledge, this is the first report in the English literature a Chinese patient with variegate porphyria with an identifiable mutation. A brief review of porphyria is presented.     

Comparison of total alkaline phosphatase and three assays for bone-specific alkaline phosphatase in childhood and adolescence

We compared serum levels of total alkaline phosphatase (TAP) and bone-specific alkaline phosphatase (BAP) as determined by three different assays (lectin affinity electrophoresis, immunoradiometric assay, enzyme-linked immunosorbent assay) in subjects aged 5–20 years suffering from X-linked hypophosphatemic rickets ( n = 14), chronic renal failure ( n = 10) and chronic cholestatic liver disease ( n = 16). Results were compared to controls of the same age and were expressed as standard deviation scores (SDS). TAP correlated significantly with BAP ( r > 0.9 for each assay; p <0.001) in controls. In children with cholestatic diseases, TAP (median SDS + 2.0) was elevated, but BAP, as measured by the electrophoretic assay, was within the reference range for most patients (median SDS: -0.4; p = 0.003 for the difference between the median SDS of TAP and BAP). In contrast, results for BAP as determined by the two immunoassays were not significantly different from TAP in any of the three patient groups ( p > 0.05 in each group for both assays). In this study, the two immunoassays did not have a detectable advantage over lectin affinity electrophoresis in the determination of BAP.     

Isolation and characterization of propagable cell lines (HUNC) from the androgen-sensitive Dunning R3327H rat prostatic adenocarcinoma

The Dunning H rat prostate tumor (R3327H) is a widely used experimental model of human prostatic adenocarcinoma (CaP). The Dunning H tumor has been characterized as androgen-sensitive, androgen-receptor (AR) positive, prostate-specific antigen and prostatic acid phosphatase (PAP) positive. To date, the tumor has been maintained by serial passage in vivo because of the lack of an in vitro cell line that retains the characteristics of the in vivo tumor. The objective of the present study was to establish a propagable cell line from R3327H adenocarcinoma that maintained androgen sensitivity and expression of AR, PSA and PAP. Tissue harvested from an in vivo R3327H tumor was dissociated with collagenase and placed into Richter's improved media (with supplements). A cytokeratin-positive epithelial cell line (HUNC- E) and a vimentin-positive stromal cell line (HUNC-S) were generated from the primary culture, subcultured continuously for >300 days, and passaged >50 times. Survival of the HUNC-E cell line in vitro depended on several media supplements, including nicotinamide, insulin, transferrin, selenium and epidermal growth factor (EGF). HUNC-E cells expressed AR and produced PSA and PAP throughout the culture period, as confirmed by immunocytochemistry and Western blot analyses. Addition of 14 nM testosterone (T) or dihydrotestosterone (DHT) to HUNC-E cells, stimulated DNA synthesis as well as anchorage-independent growth and PSA production, which demonstrated the androgen-sensitive nature of the cells in vitro. When HUNC-E and HUNC-S cells were combined in a 3:1 ratio and introduced subcutaneously into syngeneic male hosts, tumors formed in 2/3 animals with an average latency of 7 months. RT-PCR and immunocytochemical characterization of the HUNC cell lines revealed that the cells expressed several growth factors and their cognate receptors, including HGF, TGF-alpha and the TGF-betas, indicating the establishment of potential autocrine loops in the neoplastic cells. The HUNC-E and HUNC-S CaP cell lines, which retain the characteristics of the epithelial and stromal components of the in vivo R3327H tumor, will allow a more thorough and informative molecular and biological analysis of prostatic adenocarcinoma.      

Are all forms of feature binding disturbed in schizophrenia? Evidence from a central vs. peripheral distinction in working memory

In this study we investigated central and peripheral feature binding in a group of 24 high pre-morbid IQ patients with schizophrenia and 24 healthy controls. In particular, participants were asked to remember specific single (e.g., word, colour) or multiple features (e.g., coloured words) of experimental items with central (coloured word) vs. peripheral (a coloured frame) attributes in a working memory binding task. Performance of the patients was significantly inferior to that of controls, especially when required to remember the peripheral combination of multiple features. Results suggest that patients with schizophrenia may have difficulties in unitizing peripheral features in working memory.     

Human burst-forming units-erythroid need direct interaction with stem cell factor for further development

To understand the factors that regulate the early growth and development of immature erythroid progenitor cells, the burst-forming units-erythroid (BFU-E), it is necessary to have both highly purified target cells and a medium free of serum. When highly purified human blood BFU-E were cultured in a serum-free medium adequate for the growth of later erythroid progenitors, BFU-E would not grow even with the addition of recombinant human interleukin-3 (rIL-3), known to be essential for these cells. However, the addition of recombinant human stem cell factor (rSCF), which supports germ cell and pluripotential stem cell growth, stimulated BFU-E to grow equally well in serum-free as in serum-containing medium. Limiting dilution studies showed that rSCF acts directly on the BFU-E that do not require accessory cells for growth. Furthermore, rSCF was necessary for BFU-E development during the initial 7 days of culture, until these cells reached the stage of the late progenitors, the colony-forming units-erythroid (CFU-E). These studies indicate that early erythropoiesis is dependent on the direct action of SCF that not only affects early stem cells but is continually necessary for the further development of committed erythroid progenitor cells until the CFU-E stage of maturation.     

On the Similarity Between the tRNAs of Organelles and Prokaryotes

Fluorescence studies with organelle transfer RNAs separated from their cytoplasmic counterparts revealed that phenylalanine tRNA from Euglena chloroplasts or Neurospora mitochondria does not contain a fluorescent "base Y." In contrast, cytoplasmic phenylalanine tRNA from Euglena and cytoplasmic tRNA from Neurospora were found to contain fluorescent bases. The fluorescence-emission spectra of Neurospora cytoplasmic tRNAs and those of the related ascomycete Saccharomyces cerevisiue were observed to be quite different. The results support the generalization that eukaryotic tRNAs contain a fluorescent base, but indicate that their respective organelle tRNAs do not. They also indicate a striking parallelism between organelle and prokaryotic tRNAs.