Department of Department of Anatomy, Cell Biology and Physiology Works
Permanent URI for this collection
Browse
Recent Submissions
Item Rac1 Mediates Load-Driven Attenuation of mRNA Expression of Nerve Growth Factor Beta in Cartilage and Chondrocytes(International Society of Musculoskeletal and Neuronal Interactions, 2013) Shim, Joon W.; Hamamura, Kazunori; Chen, Andy; Wan, Qiaoqiao; Na, Sungsoo; Yokota, Hiroki; Anatomy, Cell Biology and Physiology, School of MedicineObjectives: To determine effect of gentle loads applied to the knee on mRNA expression of nerve growth factor, particularly, the active beta subunit (NGFβ) in cartilage and chondrocyte. Methods: Cyclic compressive loads in vivo and fluid flow in vitro were used to determine the mRNA levels. Alteration of Rac1 GTPase as well as effect of salubrinal, a specific inhibitor of eIF2α phosphatase was assessed using fluorescence resonance energy transfer (FRET)-based Rac1 biosensor. Results: Knee loading at 1 N reduced mRNA levels of NGFβ and its low affinity receptor, p75 in cartilage and subchondral bone. In cartilage, knee loading at 1 N reduced the phosphorylation level of p38 MAPK (p38-p) and activity of Rac1 GTPase. Consistent with in vivo results, fluid flow at 5 and 10 dyn/cm(2) reduced mRNA levels of NGFβ and p75 in C28/I2 human chondrocytes. SB203580, which decreases p38-p, reduced the mRNA levels of NGFβ and p75. Silencing Rac1 by siRNA decreased the levels of p38-p and NGFβ mRNA but not p75. Furthermore, administration of salubrinal reduced FRET-based activity of Rac1 as well as the mRNA levels of NGFβ and p75. Conclusions: These results provide evidence that mechanical stimulation and salubrinal may attenuate pain perception-linked NGFβ signaling through Rac1-mediated p38 MAPK.Item Intracortical Bone Remodeling Variation Shows Strong Genetic Effects(Springer, 2013) Havill, L. M.; Allen, M. R.; Harris, J. A. K.; Levine, S. M.; Coan, H. B.; Mahaney, M. C.; Nicolella, D. P.; Anatomy, Cell Biology and Physiology, School of MedicineIntracortical microstructure influences crack propagation and arrest within bone cortex. Genetic variation in intracortical remodeling may contribute to mechanical integrity and, therefore, fracture risk. Our aim was to determine the degree to which normal population-level variation in intracortical microstructure is due to genetic variation. We examined right femurs from 101 baboons (74 females, 27 males; aged 7-33 years) from a single, extended pedigree to determine osteon number, osteon area (On.Ar), haversian canal area, osteon population density, percent osteonal bone (%On.B), wall thickness (W.Th), and cortical porosity (Ct.Po). Through evaluation of the covariance in intracortical properties between pairs of relatives, we quantified the contribution of additive genetic effects (heritability [h (2)]) to variation in these traits using a variance decomposition approach. Significant age and sex effects account for 9 % (Ct.Po) to 21 % (W.Th) of intracortical microstructural variation. After accounting for age and sex, significant genetic effects are evident for On.Ar (h (2) = 0.79, p = 0.002), %On.B (h (2) = 0.82, p = 0.003), and W.Th (h (2) = 0.61, p = 0.013), indicating that 61-82 % of the residual variation (after accounting for age and sex effects) is due to additive genetic effects. This corresponds to 48-75 % of the total phenotypic variance. Our results demonstrate that normal, population-level variation in cortical microstructure is significantly influenced by genes. As a critical mediator of crack behavior in bone cortex, intracortical microstructural variation provides another mechanism through which genetic variation may affect fracture risk.Item Knee loading reduces MMP13 activity in the mouse cartilage(Springer Nature, 2013-11-01) Hamamura, Kazunori; Zhang, Ping; Zhao, Liming; Shim, Joon W.; Chen, Andy; Dodge, Todd R.; Wan, Qiaoqiao; Shih, Han; Na, Sungsoo; Lin, Chien-Chi; Sun, Hui Bin; Yokota, Hiroki; Anatomy, Cell Biology and Physiology, School of MedicineBackground: Moderate loads with knee loading enhance bone formation, but its effects on the maintenance of the knee are not well understood. In this study, we examined the effects of knee loading on the activity of matrix metalloproteinase13 (MMP13) and evaluated the role of p38 MAPK and Rac1 GTPase in the regulation of MMP13. Methods: Knee loading (0.5-3 N for 5 min) was applied to the right knee of surgically-induced osteoarthritis (OA) mice as well as normal (non-OA) mice, and MMP13 activity in the femoral cartilage was examined. The sham-loaded knee was used as a non-loading control. We also employed primary non-OA and OA human chondrocytes as well as C28/I2 chondrocyte cells, and examined MMP13 activity and molecular signaling in response to shear at 2-20 dyn/cm². Results: Daily knee loading at 1 N for 2 weeks suppressed cartilage destruction in the knee of OA mice. Induction of OA elevated MMP13 activity and knee loading at 1 N suppressed this elevation. MMP13 activity was also increased in primary OA chondrocytes, and this increase was attenuated by applying shear at 10 dyn/cm². Load-driven reduction in MMP13 was associated with a decrease in the phosphorylation level of p38 MAPK (p-p38) and NFκB (p-NFκB). Molecular imaging using a fluorescence resonance energy transfer (FRET) technique showed that Rac1 activity was reduced by shear at 10 dyn/cm² and elevated by it at 20 dyn/cm². Silencing Rac1 GTPase significantly reduced MMP13 expression and p-p38 but not p-NFκB. Transfection of a constitutively active Rac1 GTPase mutant increased MMP13 activity, while a dominant negative mutant decreased it. Conclusions: Knee loading reduces MMP13 activity at least in part through Rac1-mediated p38 MAPK signaling. This study suggests the possibility of knee loading as a therapy not only for strengthening bone but also preventing tissue degradation of the femoral cartilage.Item Sclerostin Inhibition Reverses Skeletal Fragility in an Lrp5-Deficient Mouse Model of OPPG Syndrome(American Association for the Advancement of Science, 2013) Kedlaya, Rajendra; Veera, Shreya; Horan, Daniel J.; Moss, Rachel E.; Ayturk, Ugur M.; Jacobsen, Christina M.; Bowen, Margot E.; Paszty, Chris; Warman, Matthew L.; Robling, Alexander G.; Anatomy, Cell Biology and Physiology, School of MedicineOsteoporosis pseudoglioma syndrome (OPPG) is a rare genetic disease that produces debilitating effects in the skeleton. OPPG is caused by mutations in LRP5, a WNT co-receptor that mediates osteoblast activity. WNT signaling through LRP5, and also through the closely related receptor LRP6, is inhibited by the protein sclerostin (SOST). It is unclear whether OPPG patients might benefit from the anabolic action of sclerostin neutralization therapy (an approach currently being pursued in clinical trials for postmenopausal osteoporosis) in light of their LRP5 deficiency and consequent osteoblast impairment. To assess whether loss of sclerostin is anabolic in OPPG, we measured bone properties in a mouse model of OPPG (Lrp5(-/-)), a mouse model of sclerosteosis (Sost(-/-)), and in mice with both genes knocked out (Lrp5(-/-);Sost(-/-)). Lrp5(-/-);Sost(-/-) mice have larger, denser, and stronger bones than do Lrp5(-/-) mice, indicating that SOST deficiency can improve bone properties via pathways that do not require LRP5. Next, we determined whether the anabolic effects of sclerostin depletion in Lrp5(-/-) mice are retained in adult mice by treating 17-week-old Lrp5(-/-) mice with a sclerostin antibody for 3 weeks. Lrp5(+/+) and Lrp5(-/-) mice each exhibited osteoanabolic responses to antibody therapy, as indicated by increased bone mineral density, content, and formation rates. Collectively, our data show that inhibiting sclerostin can improve bone mass whether LRP5 is present or not. In the absence of LRP5, the anabolic effects of SOST depletion can occur via other receptors (such as LRP4/6). Regardless of the mechanism, our results suggest that humans with OPPG might benefit from sclerostin neutralization therapies.Item Localized Hotspots Drive Continental Geography of Abnormal Amphibians on U.S. Wildlife Refuges(Public Library of Science, 2013-11-18) Reeves, Mari K.; Medley, Kimberly A.; Pinkney, Alfred E.; Holyoak, Marcel; Johnson, Pieter T. J.; Lannoo, Michael J.; Anatomy, Cell Biology and Physiology, School of MedicineAmphibians with missing, misshapen, and extra limbs have garnered public and scientific attention for two decades, yet the extent of the phenomenon remains poorly understood. Despite progress in identifying the causes of abnormalities in some regions, a lack of knowledge about their broader spatial distribution and temporal dynamics has hindered efforts to understand their implications for amphibian population declines and environmental quality. To address this data gap, we conducted a nationwide, 10-year assessment of 62,947 amphibians on U.S. National Wildlife Refuges. Analysis of a core dataset of 48,081 individuals revealed that consistent with expected background frequencies, an average of 2% were abnormal, but abnormalities exhibited marked spatial variation with a maximum prevalence of 40%. Variance partitioning analysis demonstrated that factors associated with space (rather than species or year sampled) captured 97% of the variation in abnormalities, and the amount of partitioned variance decreased with increasing spatial scale (from site to refuge to region). Consistent with this, abnormalities occurred in local to regional hotspots, clustering at scales of tens to hundreds of kilometers. We detected such hotspot clusters of high-abnormality sites in the Mississippi River Valley, California, and Alaska. Abnormality frequency was more variable within than outside of hotspot clusters. This is consistent with dynamic phenomena such as disturbance or natural enemies (pathogens or predators), whereas similarity of abnormality frequencies at scales of tens to hundreds of kilometers suggests involvement of factors that are spatially consistent at a regional scale. Our characterization of the spatial and temporal variation inherent in continent-wide amphibian abnormalities demonstrates the disproportionate contribution of local factors in predicting hotspots, and the episodic nature of their occurrence.Item PTEN/PI3K and MAPK signaling in protection and pathology following CNS injuries(Frontiers Media, 2013) Walker, Chandler L.; Liu, Nai-Kui; Xu, Xiao-Ming; Anatomy, Cell Biology and Physiology, School of MedicineBrain and spinal cord injuries initiate widespread temporal and spatial neurodegeneration, through both necrotic and programmed cell death mechanisms. Inflammation, reactive oxidation, excitotoxicity and cell-specific dysregulation of metabolic processes are instigated by traumatic insult and are main contributors to this cumulative damage. Successful treatments rely on prevention or reduction of the magnitude of disruption, and interfering with injurious cellular responses through modulation of signaling cascades is an effective approach. Two intracellular signaling pathways, the phosphatase and tensin homolog (PTEN)/phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling cascades play various cellular roles under normal and pathological conditions. Activation of both pathways can influence anatomical and functional outcomes in multiple CNS disorders. However, some mechanisms involve inhibiting or enhancing one pathway or the other, or both, in propagating specific downstream effects. Though many intracellular mechanisms contribute to cell responses to insult, this review examines the evidence exploring PTEN/PI3K and MAPK signaling influence on pathology, neuroprotection, and repair and how these pathways may be targeted for advancing knowledge and improving neurological outcome after injury to the brain and spinal cord.Item Sex-specific increases in myostatin and SMAD3 contribute to obesity-related insulin resistance in human skeletal muscle and primary human myotubes(American Physiological Society, 2024) Saxena, Gunjan; Gallagher, Sean; Law, Timothy D.; Maschari, Dominic; Walsh, Erin; Dudley, Courtney; Brault, Jeffrey J.; Consitt, Leslie A.; Anatomy, Cell Biology and Physiology, School of MedicineThe purpose of the present study was to determine the effects of obesity and biological sex on myostatin expression in humans and to examine the direct effects of myostatin, SMAD2, and SMAD3 on insulin signaling in primary human skeletal muscle cells (HSkMCs). For cohort 1, 15 lean [body mass index (BMI): 22.1 ± 0.5 kg/m2; n = 8 males; n = 7 females] and 14 obese (BMI: 40.6 ± 1.4 kg/m2; n = 7 males; n = 7 females) individuals underwent skeletal muscle biopsies and an oral glucose tolerance test. For cohort 2, 14 young lean (BMI: 22.4 ± 1.9 kg/m2; n = 6 males; n = 8 females) and 14 obese (BMI: 39.3 ± 7.9 kg/m2; n = 6 males; n = 8 females) individuals underwent muscle biopsies for primary HSkMC experiments. Plasma mature myostatin (P = 0.041), skeletal muscle precursor myostatin (P = 0.048), and skeletal muscle SMAD3 (P = 0.029) were elevated in obese females compared to lean females, and plasma mature myostatin (r = 0.58, P = 0.029) and skeletal muscle SMAD3 (r = 0.56, P = 0.037) were associated with insulin resistance in females but not males. Twenty-four hours of myostatin treatment impaired insulin signaling in primary HSkMCs derived from females (P < 0.024) but not males. Overexpression of SMAD3, but not SMAD2, impaired insulin-stimulated AS160 phosphorylation in HSkMCs derived from lean females (-27%, P = 0.040), whereas silencing SMAD3 improved insulin-stimulated AS160 phosphorylation and insulin-stimulated glucose uptake (25%, P < 0.014) in HSkMCs derived from obese females. These results suggest for the first time that myostatin-induced impairments in skeletal muscle insulin signaling are sex specific and that increased body fat in females is associated with detrimental elevations in myostatin and SMAD3, which contribute to obesity-related insulin resistance. NEW & NOTEWORTHY: Obesity is considered a main risk factor for the development of insulin resistance and type 2 diabetes. The present study utilizes in vivo and in vitro experiments in human skeletal muscle to demonstrate for the first time that females are inherently more susceptible to myostatin-induced insulin resistance, which is further enhanced with obesity due to increased myostatin and SMAD3 expression.Item Legal and ethical considerations around the use of existing illustrations to generate new illustrations in the anatomical sciences(Wiley, 2025) Cornwall, Jon; White, Richard; Pennefather, Patrick; Hildebrandt, Sabine; Gregory, Jill; Smith, Heather F.; Organ, Jason; Krebs, Claudia; Anatomy, Cell Biology and Physiology, School of MedicineIt is likely existing anatomical illustrations are often used as the basis for new illustrative works, given not all illustrators have access to human tissues, bodies, or prosections on which to base their illustrations. Potential issues arise with this practice in the realms of copyright infringement and plagiarism when authors are seeking to publish, a matter becoming more prevalent with the proliferation in publishing platforms and the increased adoption of generative artificial intelligence applications within academia. However, there is little published guidance that might inform authors when using an existing illustration as the basis for new work. This article provides information pertaining to copyright, copyright infringement, fair use and fair dealings, plagiarism, and the overlap of copyright and plagiarism to highlight issues of law and ethics that are relevant to the creation of illustrations. Interestingly, the determination of exactly what constitutes an "original" illustration per construction from a secondary source has not been determined in case law for anatomy illustrations. This fact illuminates the absence of a "bright-line" test for illustration reproduction and the difficulties in the objective assessment of what constitutes a "nonoriginal" illustration. The term "substantively different" is useful for determining whether illustrations derived from secondary sources can be deemed original. This article delivers guidance on how to develop illustrations with reference to determining whether copyright has been breached or plagiarism has occurred. It also provides information that will direct decision-making around illustrative content.Item Comparative Analyses and Ablation Efficiency of Thulium Fiber Laser by Stone Composition(Wolters Kluwer, 2024) Johnson, Jeffrey; Lee, Justin; Movassaghi, Miyad; Han, David; Pingle, Srinath-Reddi; Williams, James; Schulster, Michael; Gorroochurn, Prakash; Shao, Yinming; Shah, Ojas; Anatomy, Cell Biology and Physiology, School of MedicinePurpose: There are limited data on ablation effects of thulium fiber laser (TFL) settings with varying stone composition. Similarly, little is known surrounding the photothermal effects of TFL lithotripsy regarding the chemical and structural changes after visible char formation. We aim to understand the TFL's ablative efficiency across various stone types and laser settings, while simultaneously investigating the photothermal effects of TFL lithotripsy. Materials and methods: Human specimens of calcium oxalate monohydrate, calcium oxalate dihydrate, uric acid, struvite, cystine, carbonate apatite, and brushite stones were ablated using 13 prespecified settings with the Coloplast TFL Drive. Pre- and postablation mass, ablation time, and total energy were recorded. Qualitative ablative observations were recorded at 1-minute intervals with photographs and gross description. Samples were analyzed with Fourier-transform infrared spectroscopy pre- and postablation and electron microscopy postablation to assess the photothermal effects of TFL. Results: Across all settings and stone types, 0.05 J × 1000 Hz was the best numerically efficient ablation setting. When selected for more clinically relevant laser settings (ie, 10-20 W), 0.2 J × 100 Hz, short pulse was the most numerically efficient setting for calcium oxalate dihydrate, cystine, and struvite stones. Calcium oxalate monohydrate ablated with the best numerical efficiency at 0.4 J × 40 Hz, short pulse. Uric acid and carbonate apatite stones ablated with the best numerical efficiency at 0.3 J × 60 Hz, short pulse. Brushite stones ablated with the best numerical efficiency at 0.5 J × 30 Hz, short pulse. Pulse duration impacted ablation effectiveness greatly with 6/8 (75%) of inadequate ablations occurring in medium or long pulse settings. The average percent of mass lost during ablation was 57%; cystine stones averaged the highest percent mass lost at 71%. Charring was observed in 36/91 (40%) specimens. Charring was most often seen in uric acid, cystine, and brushite stones across all laser settings. Electron microscopy of char demonstrated a porous melting effect different to that of brittle fracture. Fourier-transform infrared spectroscopy of brushite char demonstrated a chemical composition change to amorphous calcium phosphate. Conclusions: We describe the optimal ablation settings based on stone composition, which may guide urologists towards more stone-specific care when using thulium laser for treating renal stones (lower energy settings would be safer for ureteral stones). For patients with unknown stone composition, lasers can be preset to target common stone types or adjusted based on visual cues. We recommend using short pulse for all TFL lithotripsy of calculi and altering the settings based on visual cues and efficiency to minimize the charring, an effect which can make the stone refractory to further dusting and fragmentation.Item The Use of Cognition by Amphibians Confronting Environmental Change: Examples from the Behavioral Ecology of Crawfish Frogs (Rana areolata)(MDPI, 2025-03-04) Lannoo, Michael J.; Stiles, Rochelle M.; Anatomy, Cell Biology and Physiology, School of MedicineAmphibian conservation concerns frequently center on the idea of 'saving' them, with the underlying assumption they are the passive victims of anthropogenic environmental change. But this approach ignores the physiological, biochemical, and behavioral flexibility amphibians have employed since they first evolved ~365 million years ago. One overlooked advantage amphibians possess in the struggle for survival, and one humans might use in their efforts to conserve them, is their brains share the same blueprint as human brains, which allows them to acquire knowledge and understanding through experiences-in other words, amphibians have cognitive capabilities that assist them in their effort to survive. Here, we use four examples from our work on the behavioral ecology of Crawfish Frogs (Rana areolata) to form hypotheses about how cognition affects amphibian reaction to environmental and social change. The first two examples describe Crawfish Frog responses to seasonality and reproductive status, the third details their reaction to ecological disturbance, and the fourth describes how their response to the same stimulus changes with growth/age. In each example, we detail the neuronal circuitry thought to be involved and hypothesize the role of cognition. We propose that as one component of our fight to conserve amphibians, researchers should consider the full range of anatomical, physiological, biochemical, and behavioral features amphibians themselves employ in their defense, which are features responsible for their historical evolutionary success up until the Anthropocene. Further, we submit that acknowledging amphibians possess cognitive abilities can enrich interpretations of not only behavioral and ecological observations but also of neuroanatomical and neurophysiological results.