Inhibition of Pediatric Glioblastoma Tumor Growth by the Anti-Cancer Agent OKN-007 in Orthotopic Mouse Xenografts

Pediatric glioblastomas (pGBM), although rare, are one of the leading causes of cancer-related deaths in children, with tumors essentially refractory to existing treatments. Here, we describe the use of conventional and advanced in vivo magnetic resonance imaging (MRI) techniques to assess a novel orthotopic xenograft pGBM mouse (IC-3752GBM patient-derived culture) model, and to monitor the effects of the anti-cancer agent OKN-007 as an inhibitor of pGBM tumor growth. Immunohistochemistry support data is also presented for cell proliferation and tumor growth signaling. OKN-007 was found to significantly decrease tumor volumes (p<0.05) and increase animal survival (p<0.05) in all OKN-007-treated mice compared to untreated animals. In a responsive cohort of treated animals, OKN-007 was able to significantly decrease tumor volumes (p<0.0001), increase survival (p<0.001), and increase diffusion (p<0.01) and perfusion rates (p<0.05). OKN-007 also significantly reduced lipid tumor metabolism in responsive animals [(Lip1.3 and Lip0.9)-to-creatine ratio (p<0.05)], as well as significantly decrease tumor cell proliferation (p<0.05) and microvessel density (p<0.05). Furthermore, in relationship to the PDGFRα pathway, OKN-007 was able to significantly decrease SULF2 (p<0.05) and PDGFR-α (platelet-derived growth factor receptor-α) (p<0.05) immunoexpression, and significantly increase decorin expression (p<0.05) in responsive mice. This study indicates that OKN-007 may be an effective anti-cancer agent for some patients with pGBMs by inhibiting cell proliferation and angiogenesis, possibly via the PDGFRα pathway, and could be considered as an additional therapy for pediatric brain tumor patients.     

Evaluating Sierra Nevada Yellow-Legged Frog Distribution Using Environmental DNA

Genetic tools that identify species from trace DNA samples could supplement traditional survey methods to clarify distributional limits of rare species. For species with legal habitat protection, elevational limits of distributions are used to determine where management actions may affect endangered species. The endangered Sierra Nevada yellow-legged frog (Rana sierrae) generally is found down to 1,370 m, but in the Plumas National Forest, California, USA, there are a number of historical records below this elevation, resulting in protections extending to 1,067 m. This species is phenotypically similar to the foothill yellow-legged frog (R. boylii), with which it occasionally hybridizes. We used a combination of genetic methods to investigate the fine-scale distribution of the Sierra Nevada yellow-legged frog in the Plumas National Forest. We collected and analyzed environmental DNA (eDNA) samples from all accessible lower elevation sites with records of Sierra Nevada yellow-legged frog (n = 17) and swabbed 220 individuals for genetic identification from 2016–2018 to clarify the distribution of this endangered species. We created a climatic suitability model using the validated Sierra Nevada yellow-legged frog records and current (1970–2000) climate models to assess additional highly suitable localities for Sierra Nevada yellow-legged frog presence using eDNA capture. We did not confirm detection of Sierra Nevada yellow-legged frog eDNA at any historical sites and identified all swabbed individuals from below 1,370 m (n = 144) as foothill yellow-legged frogs. We located a new Sierra Nevada yellow-legged frog site (at 1,919 m) during surveys guided by the climatic suitability model. It does not appear after extensive eDNA and genetic sampling that the Sierra Nevada yellow-legged frog occurs below 1,370 m in this portion of their range at present. Our results show that eDNA sampling can be used as an effective management tool to evaluate historical locations and previously unknown suitable localities for current presence of a species of interest. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.     

Proteomic analysis of Col11a1-associated protein complexes

Cartilage plays an essential role during skeletal development within the growth plate and in articular joint function. Interactions between the collagen fibrils and other extracellular matrix molecules maintain structural integrity of cartilage, orchestrate complex dynamic events during embryonic development, and help to regulate fibrillogenesis. To increase our understanding of these events, affinity chromatography and liquid chromatography/tandem mass spectrometry were used to identify proteins that interact with the collagen fibril surface via the amino terminal domain of collagen α1(XI) a protein domain that is displayed at the surface of heterotypic collagen fibrils of cartilage. Proteins extracted from fetal bovine cartilage using homogenization in high ionic strength buffer were selected based on affinity for the amino terminal noncollagenous domain of collagen α1(XI). MS was used to determine the amino acid sequence of tryptic fragments for protein identification. Extracellular matrix molecules and cellular proteins that were identified as interacting with the amino terminal domain of collagen α1(XI) directly or indirectly, included proteoglycans, collagens, and matricellular molecules, some of which also play a role in fibrillogenesis, while others are known to function in the maintenance of tissue integrity. Characterization of these molecular interactions will provide a more thorough understanding of how the extracellular matrix molecules of cartilage interact and what role collagen XI plays in the process of fibrillogenesis and maintenance of tissue integrity. Such information will aid tissue engineering and cartilage regeneration efforts to treat cartilage tissue damage and degeneration.     

Phosphatidylglycerol provides short-term prophylaxis against respiratory syncytial virus infection

Respiratory syncytial virus (RSV) causes respiratory tract infections in young children, and significant morbidity and mortality in the elderly, immunosuppressed, and immunocompromised patients and in patients with chronic lung diseases. Recently, we reported that the pulmonary surfactant phospholipid palmitoyl-oleoyl-phosphatidylglycerol (POPG) inhibited RSV infection in vitro and in vivo by blocking viral attachment to epithelial cells. Simultaneous application of POPG along with an RSV challenge to mice markedly attenuated infection and associated inflammatory responses. Based on these findings, we expanded our studies to determine whether POPG is effective for prophylaxis and postinfection treatment for RSV infection. In vitro application of POPG at concentrations of 0.2–1.0 mg/ml at 24 h after RSV infection of HEp-2 cells suppressed interleukin-8 production up to 80% and reduced viral plaque formation by 2–6 log units. In vivo, the turnover of POPG in mice is relatively rapid, making postinfection application impractical. Intranasal administration of POPG (0.8–3.0 mg), 45 min before RSV inoculation in mice reduced viral infection by 1 log unit, suppressed inflammatory cell appearance in the lung, and suppressed virus-elicited interferon-γ production. These findings demonstrate that POPG is effective for short-term protection of mice against subsequent RSV infection and that it has potential for application in humans.     

Nitrogen Identity Drives Differential Impacts of Nutrients on Coral Bleaching and Mortality

Ecosystems - Nitrogen pollution increases the susceptibility of corals to heat-induced bleaching. However, different forms of nitrogen (nitrate vs. ammonium/urea) may have different impacts on...     

Chironomid assemblages from seabird-affected High Arctic ponds

Seabirds can shunt nutrients and contaminants from marine to terrestrial ecosystems by forming dense breeding colonies and releasing wastes to these sites. A large colony of seabirds at Cape Vera (Devon Island, High Arctic Canada) has resulted in eutrophic conditions and potentially toxic concentrations of sedimentary metals in several freshwater ponds that drain their nesting sites. Here, we investigated the effects of elevated nutrient and sedimentary metal concentrations on the distribution of subfossil chironomids in surface sediments from 21 ponds that span a gradient of seabird influence. Although many ponds registered high nutrient concentrations (e.g., mean TP = 45 μg l ⁻¹), eutrophic taxa typical of temperate waters were not common, with most assemblages being dominated by morphotypes of Psectrocladius and Tanytarsina, as well as Corynoneura arctica-type, and Metriocnemus hygropetricus-type. Although the ponds within and outside the area influenced by seabirds contained largely similar taxa, variations did exist in the relative abundances of the different species. Lakewater pH was the only measured environmental variable that explained statistically significant amounts of variation in the chironomid assemblages. Although direct effects of pH on chironomids cannot be ruled out, pH is likely tracking production-related changes driven by limnetic dissolved inorganic carbon dynamics. Sediment cores collected from seabird-affected and seabird-free ponds showed a greater number of chironomid taxa and higher head capsule abundances in the pond receiving seabird inputs. Chironomid assemblages in both cores recorded increased abundances in recent decades, likely in response to warmer conditions and lengthened growing seasons.     

A disease-associated polymorphism alters splicing of the human CD45 phosphatase gene by disrupting combinatorial repression by heterogeneous nuclear ribonucleoproteins (hnRNPs)

Alternative splicing is typically controlled by complexes of regulatory proteins that bind to sequences within or flanking variable exons. The identification of regulatory sequence motifs and the characterization of sequence motifs bound by splicing regulatory proteins have been essential to predicting splicing regulation. The activation-responsive sequence (ARS) motif has previously been identified in several exons that undergo changes in splicing upon T cell activation. hnRNP L binds to this ARS motif and regulates ARS-containing exons; however, hnRNP L does not function alone. Interestingly, the proteins that bind together with hnRNP L differ for different exons that contain the ARS core motif. Here we undertake a systematic mutational analysis of the best characterized context of the ARS motif, namely the ESS1 sequence from CD45 exon 4, to understand the determinants of binding specificity among the components of the ESS1 regulatory complex and the relationship between protein binding and function. We demonstrate that different mutations within the ARS motif affect specific aspects of regulatory function and disrupt the binding of distinct proteins. Most notably, we demonstrate that the C77G polymorphism, which correlates with autoimmune disease susceptibility in humans, disrupts exon silencing by preventing the redundant activity of hnRNPs K and E2 to compensate for the weakened function of hnRNP L. Therefore, these studies provide an important example of the functional relevance of combinatorial function in splicing regulation and suggest that additional polymorphisms may similarly disrupt function of the ESS1 silencer.     

Allometry, bilateral asymmetry and sexual differences in the vocal tract of common eiders Somateria mollissima and king eiders S. spectabilis

Intraspecific sexual differences, high variation, and positive allometry of sexually-selected external display structures are common. Many sexually-selected anatomical specializations occur in the avian vocal tract but intraspecific variation and allometry have been investigated little. The tracheal bulla bulla syringealis occurs in males of most duck species. We quantified variation and size-scaling of the bulla, plus sexual differences in size of trachea, bronchi, and vocal muscles, for 62 common eiders Somateria mollissima and 51 king eiders S. spectabilis. Trends were similar in both species. Bullar ossification and definitive size occurred early in life: bullar size did not differ between first-year and older males. Bullar size did not vary more than size of other body parts (CVs of 3.4–7.0% for bullar length and breadth). Bullar size scaled to body size with negative allometry or isometry. Vocal muscles were 10–50% thicker in males than females, a much greater sexual difference than in body size (CVs of 3–6% on linear body-size variables). Vocal muscles were larger on the left side in both sexes and bilateral asymmetry was slightly more pronounced in males. Low variation and a trend towards negative allometry suggest that bullar size is under stabilizing selection; if bullar size affects vocal attributes of voice, then the latter cannot be condition-dependent. We recommend comparative research on vocal communication, vocal individuality and vocal-tract anatomy and function in eiders and other ducks.     

Comment arising from a paper by Wittmer et al.: hypothesis testing for top-down and bottom-up effects in woodland caribou population dynamics

Conservation strategies for populations of woodland caribou Rangifer tarandus caribou frequently emphasize the importance of predator–prey relationships and the availability of lichen-rich late seral forests, yet the importance of summer diet and forage availability to woodland caribou survival is poorly understood. In a recent article, Wittmer et al. (Can J Zool 83:407–418, 2005b) concluded that woodland caribou in British Columbia were declining as a consequence of increased predation that was facilitated by habitat alteration. Their conclusion is consistent with the findings of other authors who have suggested that predation is the most important proximal factor limiting woodland caribou populations (Bergerud and Elliot in Can J Zool 64:1515–1529, 1986; Edmonds in Can J Zool 66:817–826, 1988; Rettie and Messier in Can J Zool 76:251–259, 1998; Hayes et al. in Wildl Monogr 152:1–35, 2003). Wittmer et al. (Can J Zool 83:407–418, 2005b) presented three alternative, contrasting hypotheses for caribou decline that differed in terms of predicted differences in instantaneous rates of increase, pregnancy rates, causes of mortality, and seasonal vulnerability to mortality (Table 1, p 258). These authors rejected the hypotheses that food or an interaction between food and predation was responsible for observed declines in caribou populations; however, the use of pregnancy rate, mortality season and cause of mortality to contrast the alternative hypotheses is problematic. We argue here that the data employed in their study were insufficient to properly evaluate a predation-sensitive foraging hypothesis for caribou decline. Empirical data on seasonal forage availability and quality and plane of nutrition of caribou would be required to test the competing hypotheses. We suggest that methodological limitations in studies of woodland caribou population dynamics prohibit proper evaluation of the mechanism of caribou population declines and fail to elucidate potential interactions between top-down and bottom-up effects on populations. An erratum to this article can be found at