Modulation of Tmem135 Leads to Retinal Pigmented Epithelium Pathologies in Mice.

Purpose: Aging is a critical risk factor for the development of retinal diseases, but how aging perturbs ocular homeostasis and contributes to disease is unknown. We identified transmembrane protein 135 (Tmem135) as a gene important for regulating retinal aging and mitochondrial dynamics in mice. Overexpression of Tmem135 causes mitochondrial fragmentation and pathologies in the hearts of mice. In this study, we examine the eyes of mice overexpressing wild-type Tmem135 (Tmem135 TG) and compare their phenotype to Tmem135 mutant mice. Methods: Eyes were collected for histology, immunohistochemistry, electron microscopy, quantitative PCR, and Western blot analysis. Before tissue collection, electroretinography (ERG) was performed to assess visual function. Mouse retinal pigmented epithelium (RPE) cultures were established to visualize mitochondria. Results: Pathologies were observed only in the RPE of Tmem135 TG mice, including degeneration, migratory cells, vacuolization, dysmorphogenesis, cell enlargement, and basal laminar deposit formation despite similar augmented levels of Tmem135 in the eyecup (RPE/choroid/sclera) and neural retina. We observed reduced mitochondria number and size in the Tmem135 TG RPE. ERG amplitudes were decreased in 365-day-old mice overexpressing Tmem135 that correlated with reduced expression of RPE cell markers. In Tmem135 mutant mice, RPE cells are thicker, smaller, and denser than their littermate controls without any signs of degeneration. Conclusions: Overexpression and mutation of Tmem135 cause contrasting RPE abnormalities in mice that correlate with changes in mitochondrial shape and size (overfragmented in TG vs. overfused in mutant). We conclude proper regulation of mitochondrial homeostasis by TMEM135 is critical for RPE health.

Anorexia nervosa manifesting as massive ascites, hypercholesterolemia, and sequential binge eating in an 11-year-old girl: A case report.

RATIONALE: Anorexia nervosa (AN) is a serious eating disorder associated with a distorted body image. Hypercholesterolemia has been found in patients with AN but the mechanism of hyperlipidemia in AN remains little known. Ascites in patients with AN has been attributed to hypoalbuminemia and liver diseases, but massive ascites without the aforementioned etiologies has never been reported in AN. PATIENT CONCERNS: An 11-year-old girl was admitted for exclusion of organic underlying diseases due to severe body weight loss (18% within 3 weeks), poor appetite, and hypercholesterolemia (274 mg/dL). She complained of heartburn sensation, nausea, vomiting, constipation, and postprandial dull abdominal pain with fullness. DIAGNOSES: The patient's condition met with all 3 of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for diagnosing AN. On admission, her total cholesterol level was 337 mg/dL and hypocomplementemia (C3 55.5 mg/dL) was also found. Abdominal sonography and computed tomography scans showed massive ascites. However, neither proteinuria nor hypoalbuminemia was found. Upper gastroduodenal endoscopy showed chronic superficial gastritis and colonoscopy revealed negative findings. Ascites obtained by paracentesis demonstrated a transudate without bacterial infection, tuberculosis, or pancreatitis. Exploratory laparoscopy showed nonpurulent ascites. However, biopsies from the small intestine, mesentery, and liver showed chronic inflammation and fibrosis. INTERVENTIONS: The intensive nutritional therapy by increasing total energy intake stepwise with a combination of high-energy formula and her favorite foods. OUTCOMES: Her hypercholesterolemia, hypocomplementemia, and massive ascites resolved after her weight was restored. She developed binge eating with continuous weight gain after discharge. Her weight significantly increased to an obese level (body mass index [BMI] 25.9 kg/m) after loss to follow-up for 4 years until she returned to our emergency room due to suicide attempt. CONCLUSION: Diagnostic crossover between subtypes in anorexia nervosa might be a potential risk factor for illness severity and poor prognosis. AN can manifest as massive ascites with normal albumin concentrations that could possibly be due to chronic inflammation of the intestinal serosa, mesentery, and peritoneal surface of the liver.

Metabolic alterations caused by the mutation and overexpression of the Tmem135 gene.

IMPACT STATEMENT: Mitochondria are dynamic organelles undergoing fission and fusion. Proper regulation of this process is important for healthy aging process, as aberrant mitochondrial dynamics are associated with several age-related diseases/pathologies. However, it is not well understood how imbalanced mitochondrial dynamics may lead to those diseases and pathologies. Here, we aimed to determine metabolic alterations in tissues and cells from mouse models with over-fused (fusion > fission) and over-fragmented (fusion < fission) mitochondria that display age-related disease pathologies. Our results indicated tissue-dependent sensitivity to these mitochondrial changes, and metabolic pathways likely affected by aberrant mitochondrial dynamics. This study provides new insights into how dysregulated mitochondrial dynamics could lead to functional abnormalities of tissues and cells.

Loss of Chondroitin Sulfate Modification Causes Inflammation and Neurodegeneration in skt Mice.

One major aspect of the aging process is the onset of chronic, low-grade inflammation that is highly associated with age-related diseases. The molecular mechanisms that regulate these processes have not been fully elucidated. We have identified a spontaneous mutant mouse line, small with kinky tail (skt), that exhibits accelerated aging and age-related disease phenotypes including increased inflammation in the brain and retina, enhanced age-dependent retinal abnormalities including photoreceptor cell degeneration, neurodegeneration in the hippocampus, and reduced lifespan. By positional cloning, we identified a deletion in chondroitin sulfate synthase 1 (Chsy1) that is responsible for these phenotypes in skt mice. CHSY1 is a member of the chondroitin N-acetylgalactosaminyltransferase family that plays critical roles in the biosynthesis of chondroitin sulfate, a glycosaminoglycan (GAG) that is attached to the core protein to form the chondroitin sulfate proteoglycan (CSPG). Consistent with this function, the Chsy1 mutation dramatically decreases chondroitin sulfate GAGs in the retina and hippocampus. In addition, macrophage and neutrophil populations appear significantly altered in the bone marrow and spleen of skt mice, suggesting an important role for CHSY1 in the functioning of these immune cell types. Thus, our study reveals a previously unidentified impact of CHSY1 in the retina and hippocampus. Specifically, chondroitin sulfate (CS) modification of proteins by CHSY1 appears critical for proper regulation of immune cells of the myeloid lineage and for maintaining the integrity of neuronal tissues, since a defect in this gene results in increased inflammation and abnormal phenotypes associated with age-related diseases.

Reactive oxygen species-mediated switching expression of MMP-3 in stromal fibroblasts and cancer cells during prostate cancer progression.

Studies on the aberrant control of extracellular matrices (ECMs) have mainly focused on the role of malignant cells but less on that of stromal fibroblasts during cancer development. Herein, by using paired normal and prostate cancer-associated stromal fibroblasts (CAFs) derived from a coculture cell model and clinical patient samples, we demonstrated that although CAFs promoted prostate cancer growth, matrix metalloproteinase-3 (MMP-3) was lower in CAFs but elevated in prostate cancer cells relative to their normal counterparts. Furthermore, hydrogen peroxide was characterized as the central modulator for altered MMP-3 expression in prostate cancer cells and CAFs, but through different regulatory mechanisms. Treatment of CAFs but not prostate cancer cells with hydrogen peroxide directly inhibited mmp-3 promoter activity with concomitant nuclear translocation of nuclear factor-κB (NF-κB), indicating that NF-κB is the downstream pathway for the transcriptional repression of MMP-3 in CAFs. Hydrogen peroxide reduced thrombospondin 2 (an MMP-3 suppressor) expression in prostate cancer cells by upregulating microRNA-128. To the best of our knowledge, this is the first study to demonstrate the crucial role of reactive oxygen species in the switching expression of MMP-3 in stromal fibroblasts and prostate cancer cells during tumor progression, clarifying how the tumor microenvironment modulates ECM homeostasis control.

Metabolomics Identifies Metabolic Markers of Maturation in Human Pluripotent Stem Cell-Derived Cardiomyocytes.

Cardiovascular disease is a leading cause of death worldwide. Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) hold immense clinical potential and recent studies have enabled generation of virtually pure hPSC-CMs with high efficiency in chemically defined and xeno-free conditions. Despite these advances, hPSC-CMs exhibit an immature phenotype and are arrhythmogenic in vivo, necessitating development of strategies to mature these cells. hPSC-CMs undergo significant metabolic alterations during differentiation and maturation. A detailed analysis of the metabolic changes accompanying maturation of hPSC-CMs may prove useful in identifying new strategies to expedite hPSC-CM maturation and also may provide biomarkers for testing or validating hPSC-CM maturation. In this study we identified global metabolic changes which take place during long-term culture and maturation of hPSC-CMs derived from three different hPSC lines. We have identified several metabolic pathways, including phospholipid metabolism and pantothenate and Coenzyme A metabolism, which showed significant enrichment upon maturation in addition to fatty acid oxidation and metabolism. We also identified increases in glycerophosphocholine and the glycerophosphocholine:phosphocholine ratio as potential metabolic biomarkers of maturation. These biomarkers were also affected in a similar manner during murine heart development in vivo. These results support that hPSC-CM maturation is associated with extensive metabolic changes in metabolic network utilization and understanding the roles of these metabolic changes has the potential to develop novel approaches to monitor and expedite hPSC-CM maturation.

Cyproheptadine use in hepatocellular carcinoma.

This study was conducted to compare the effectiveness of Cyproheptadine (CY) use in patients with different stages of HCC who received different therapeutic modalities; such a comparison has not been conducted by previous large, prospective, randomized studies. We conducted a cohort study using the Taiwan Cancer Registry Database for analysis. We included patients diagnosed as having HCC from January 1, 2002, to December 31, 2011. The patient cohort comprised those who received different treatments, and we compared patients who received CY with those who did not. In total, 70,885 patients were included, and the mean follow-up duration was 1.95 years. The adjusted hazard ratio (aHR) of all-cause deaths significantly decreased in all stages in the patients who received palliative treatments with CY use compared with those who received palliative treatments without CY use (all P < 0.0001 and aHR = 0.76, 0.80, 0.66, and 0.66 for stages I, II, III, and IV, respectively). Among the patients who received no treatment, CY use alone reduced the risk of all-cause deaths in stages I-IV (all P < 0.0001 and aHR = 0.61, 0.57, 0.54, and 0.52 for stages I, II, III, and IV, respectively). Among the patients with clinical stage I-II HCC (as determined by the American Joint Committee on Cancer) who received curative treatments, CY use did not reduce all-cause deaths. CY use might improve survival in patients with HCC receiving palliative treatments or no treatment regardless of clinical stages.

Mouse Tmem135 mutation reveals a mechanism involving mitochondrial dynamics that leads to age-dependent retinal pathologies.

While the aging process is central to the pathogenesis of age-dependent diseases, it is poorly understood at the molecular level. We identified a mouse mutant with accelerated aging in the retina as well as pathologies observed in age-dependent retinal diseases, suggesting that the responsible gene regulates retinal aging, and its impairment results in age-dependent disease. We determined that a mutation in the transmembrane 135 (Tmem135) is responsible for these phenotypes. We observed localization of TMEM135 on mitochondria, and imbalance of mitochondrial fission and fusion in mutant Tmem135 as well as Tmem135 overexpressing cells, indicating that TMEM135 is involved in the regulation of mitochondrial dynamics. Additionally, mutant retina showed higher sensitivity to oxidative stress. These results suggest that the regulation of mitochondrial dynamics through TMEM135 is critical for protection from environmental stress and controlling the progression of retinal aging. Our study identified TMEM135 as a critical link between aging and age-dependent diseases.

Genetic basis of age-dependent synaptic abnormalities in the retina.

Understanding the normal aging process will help us determine the mechanisms of how age-related diseases are caused and progress. A/J inbred mice have been shown to exhibit accelerated aging phenotypes in the retina including increased inflammation and photoreceptor cell degeneration, which resemble human aging symptoms. C57BL/6J (B6) inbred mice are less susceptible for these abnormalities, indicating the existence of genetic factor(s) that affect their severity. In this study, we determined that another age-dependent phenotype, ectopic synapse formation, is also accelerated in the A/J retina compared to the B6 retina. Through genetic mapping utilizing recombinant inbred strains, we identified quantitative trait loci (QTLs) on chromosome 7 and 19, which contribute to abnormal retinal synapses as well as other age-dependent phenotypes. Using consomic single chromosome substitution lines where a single chromosome is from A/J and the rest of the genome is B6, we investigated the individual effect of each QTL on retinal aging phenotypes. We observed that both QTLs independently contribute to abnormal retinal synapses, reduction in the number of cone cells, and an up-regulation of retinal stress marker, glial fibrillary acidic protein (GFAP). Mice with a single chromosome substitution on chromosome 19 also exhibited an increase in inflammatory cells, which is characteristic of aging and age-related macular degeneration. Thus, we identified QTLs that are independently capable of affecting the severity and progression of age-dependent retinal abnormalities in mice.

Role of antioxidant enzymes in redox regulation of N-methyl-D-aspartate receptor function and memory in middle-aged rats.

Overexpression of superoxide dismutase 1 (SOD1) in the hippocampus results in age-dependent impaired cognition and altered synaptic plasticity suggesting a possible model for examining the role of oxidative stress in senescent neurophysiology. However, it is unclear if SOD1 overexpression involves an altered redox environment and a decrease in N-methyl-D-aspartate receptor (NMDAR) synaptic function reported for aging animals. Viral vectors were used to express SOD1 and green fluorescent protein (SOD1 + GFP), SOD1 and catalase (SOD1 + CAT), or GFP alone in the hippocampus of middle-aged (17 months) male Fischer 344 rats. We confirm that SOD1 + GFP and SOD1 + CAT reduced lipid peroxidation indicating superoxide metabolites were primarily responsible for lipid peroxidation. SOD1 + GFP impaired learning, decreased glutathione peroxidase activity, decreased glutathione levels, decreased NMDAR-mediated synaptic responses, and impaired long-term potentiation. Co-expression of SOD1 + CAT rescued the effects of SOD1 expression on learning, redox measures, and synaptic function suggesting the effects were mediated by excess hydrogen peroxide. Application of the reducing agent dithiolthreitol to hippocampal slices increased the NMDAR-mediated component of the synaptic response in SOD1 + GFP animals relative to animals that overexpress SOD1 + CAT indicating that the effect of antioxidant enzyme expression on NMDAR function was because of a shift in the redox environment. The results suggest that overexpression of neuronal SOD1 and CAT in middle age may provide a model for examining the role of oxidative stress in senescent physiology and the progression of age-related neurodegenerative diseases.

Serum protein oxidation by diesel exhaust particles: effects on oxidative stress and inflammatory response in vitro.

Considerable evidence shows a key role for protein modification in the adverse effects of chemicals; however, the interaction of diesel exhaust particles (DEP) with proteins and the resulting biological activity remains unclear. DEP and carbon black (CB) suspensions with and without bovine serum albumin (BSA) were used to elucidate the biological effects of air pollutants. The DEP and CB samples were then divided into suspensions and supernatants. Two important goals of the interaction of DEP with BSA were as follows: (1) understanding BSA modification by particles and (2) investigating the effects of particles bound with BSA and the corresponding supernatants on cellular oxidative stress and inflammation. We observed significant free amino groups production was caused by DEP. Using liquid chromatography-mass spectrometry (LC-MS), we observed that BSA was significantly oxidised by DEP in the supernatants and that the peptides ETYGDMADCCEK, MPCTEDYLSLILNR and TVMENFVAFVDK, derived BSA-DEP conjugates, were also oxidised. In A549 cells, DEP-BSA suspensions and the corresponding supernatants reduced 8-hydroxy-2'-deoxyguanosine (8-OHdG) production and increased interleukin-6 (IL-6) levels when compared to DEP solutions without BSA. Our findings suggest that oxidatively modified forms of BSA caused by DEP could lead to oxidative stress and the activation of inflammation.

[Oxidative stress inhibits the protective effects of insulin-like growth factor-1 on cortical neurons of neonatal rat].

OBJECTIVE: To explore the protective effects of insulin-like growth factor-1(IGF-1) on the survival and apoptosis of cortical neurons of neonatal rat under oxidative stress and its significance. METHOD: Primary cortical neurons from newborn rat were cultured and the oxidative stress model was established. Then cells were randomly divided into IGF-1 group and control group. The concentration of LDH in supernatant was detected. Cell survival was determined with MTT assay and the expression of active Caspase-3 was measured using Western Blotting. RESULT: (1) The values of LDH gradually decreased with the increasing IGF-1 added to the cells [(0.5065 ± 0.0064) to (0.435 ± 0.0065), (P < 0.01)], but when the concentration of IGF-1 reached a certain level (> 25 ng/ml), there were no longer obvious effects on the level of LDH [(0.42 ± 0.012) to (0.418 ± 0.0098), (P > 0.05)]; Western blot showed that the level of active Caspase-3 was significantly decreased after treatment with IGF-1 [(0.662 ± 0.033) to (0.199 ± 0.01), (P < 0.01)]. (2) Compared with control group, without or with low concentration of H2O2 (0 - 40 µM), the values of LDH and the expression of active Caspase-3 in IGF-1 group were significantly decreased[(1.518 ± 0.137) to (1.068 ± 0.067), (P < 0.05) and 0.850 ± 0.042 to 0.597 ± 0.03, P < 0.01, respectively] while the values of MTT obviously elevated [(0.773 ± 0.062) to (1.196 ± 0.057), (P < 0.05)]; but with higher concentration (≥ 60 µM) of H2O2, the values of LDH and MTT and the expression of active Caspase-3 in IGF-1 group all had no significant difference (P > 0.05). (3) When the concentration of H2O2 reached 60 µM and higher, whatever concentration of IGF-1 could not lower the level of LDH compared with control group [(2.376 ± 0.04) to (2.442 ± 0.046), (P > 0.05)]. CONCLUSIONS: Oxidative stress can induce IGF-1 resistance of cortical neurons in neonatal rat, and even increasing the concentration of IGF-1 can not restore their sensitivity to IGF-1.

Sodium pyruvate reduces hypoxic-ischemic injury to neonatal rat brain.

BACKGROUND: Neonatal hypoxia-ischemia (HI) remains a major cause of severe brain damage and is often associated with high mortality and lifelong disability. Immature brains are extremely sensitive to HI, shown as prolonged mitochondrial neuronal death. Sodium pyruvate (SP), a substrate of the tricarboxylic acid cycle and an extracellular antioxidant, has been considered as a potential treatment for hypoxic-ischemic encephalopathy, but its effects have not been evaluated in appropriate animal models for hypoxic-ischemic encephalopathy. METHODS: This investigation used primary cortical neuron cultures derived from neonatal rats subjected to oxygen and glucose deprivation (OGD) and a well-established neonatal rat HI model. RESULTS: HI caused brain tissue loss and impaired sensorimotor function and spatial memory whereas SP significantly reduced brain damage and improved neurological performance. These neuroprotective effects of SP are likely the result of improved cerebral metabolism as demonstrated by maintaining adenosine triphosphate (ATP) levels and preventing an increase in intracellular reactive oxygen species (ROS) levels. SP treatment also decreased levels of Bax, a death signal for immature neurons, blocked caspase-3 activation, and activated a key survival signaling kinase, Akt, both in vitro and in vivo. CONCLUSION: SP protected neonatal brain from hypoxic-ischemic injury through maintaining cerebral metabolism and mitochondrial function.

Disruption of NMDAR-CRMP-2 signaling protects against focal cerebral ischemic damage in the rat middle cerebral artery occlusion model.

Collapsin response mediator protein 2 (CRMP-2), traditionally viewed as an axon/dendrite specification and axonal growth protein, has emerged as nidus in regulation of both pre- and post-synaptic Ca ( 2+) channels. Building on our discovery of the interaction and regulation of Ca ( 2+) channels by CRMP-2, we recently identified a short sequence in CRMP-2 which, when appended to the transduction domain of HIV TAT protein, suppressed acute, inflammatory and neuropathic pain in vivo by functionally uncoupling CRMP-2 from the Ca ( 2+) channel. Remarkably, we also found that this region attenuated Ca ( 2+) influx via N-methylD-Aspartate receptors (NMDARs) and reduced neuronal death in a moderate controlled cortical impact model of traumatic brain injury (TBI). Here, we sought to extend these findings by examining additional neuroprotective effects of this peptide (TAT-CBD3) and exploring the biochemical mechanisms by which TAT-CBD3 targets NMDARs. We observed that an intraperitoneal injection of TAT-CBD3 peptide significantly reduced infarct volume in an animal model of focal cerebral ischemia. Neuroprotection was observed when TAT-CBD3 peptide was given either prior to or after occlusion but just prior to reperfusion. Surprisingly, a direct biochemical complex was not resolvable between the NMDAR subunit NR2B and CRMP-2. Intracellular application of TAT-CBD3 failed to inhibit NMDAR current. NR2B interactions with the post synaptic density protein 95 (PSD-95) remained intact and were not disrupted by TAT-CBD3. Peptide tiling of intracellular regions of NR2B revealed two 15-mer sequences, in the carboxyl-terminus of NR2B, that may confer binding between NR2B and CRMP-2 which supports CRMP-2's role in excitotoxicity and neuroprotection.

Influence of viral vector-mediated delivery of superoxide dismutase and catalase to the hippocampus on spatial learning and memory during aging.

AIMS: Studies employing transgenic mice indicate that overexpression of superoxide dismutase 1 (SOD1) improves memory during aging. It is unclear whether the improvement is due to a lifetime of overexpression, decreasing the accumulation of oxidized molecules, or if increasing antioxidant enzymes in older animals could reduce oxidative damage and improve cognitive function. We used adeno-associated virus to deliver antioxidant enzymes (SOD1, SOD2, catalase [CAT], and SOD1+CAT) to the hippocampus of young (4 months) and aged (19 months) F344/BN F1 male rats and examined memory-related behavioral performance 1 month and 4 months postinjection. RESULTS: Overexpression of antioxidant enzymes reduced oxidative damage; however, memory function was not related to the level of oxidative damage. Increased expression of SOD1, initiated in advanced age, impaired learning. Increased expression of SOD1+CAT provided protection from impairments associated with overexpression of SOD1 alone and appears to guard against cognitive impairments in advanced age. INNOVATION: Viral vector gene delivery provides a novel approach to test the hypothesis that increased expression of antioxidant enzymes, specifically in hippocampal neurons, will provide protection from age-related cognitive decline. Further, expression of multiple vectors permits more detailed investigation of mechanistic pathways. CONCLUSION: Oxidative stress is a likely component of aging; however, it is unclear whether increased production of reactive oxygen species or the accumulation of oxidative damage is the primary cause of functional decline. The results provide support for the idea that altered redox-sensitive signaling rather than the accumulation of damage may be of greater significance in the emergence of age-related learning and memory deficits.

Influence of late-life exposure to environmental enrichment or exercise on hippocampal function and CA1 senescent physiology.

Aged (20-22 months) male Fischer 344 rats were randomly assigned to sedentary (A-SED), environmentally-enriched (A-ENR), or exercise (A-EX) conditions. After 10-12 weeks of differential experience, the 3 groups of aged rats and young sedentary controls were tested for physical and cognitive function. Spatial discrimination learning and memory consolidation, tested on the water maze, were enhanced in environmentally-enriched compared with sedentary. A-EX exhibited improved and impaired performance on the cue and spatial task, respectively. Impaired spatial learning in A-EX was likely due to a bias in response selection associated with exercise training, as object recognition memory improved for A-EX rats. An examination of senescent hippocampal physiology revealed that enrichment and exercise reversed age-related changes in long-term depression (LTD) and long-term potentiation (LTP). Rats in the enrichment group exhibited an increase in cell excitability compared with the other 2 groups of aged animals. The results indicate that differential experience biased the selection of a spatial or a response strategy and factors common across the 2 conditions, such as increased hippocampal activity associated with locomotion, contribute to reversal of senescent synaptic plasticity.

Delayed IGF-1 treatment reduced long-term hypoxia-ischemia-induced brain damage and improved behavior recovery of immature rats.

Cerebral hypoxia-ischemia during the perinatal period is the single most important cause of acute newborn mortality and chronic disability. Despite our increasing understanding of the mechanisms of neuronal injury, an effective clinical therapy has yet to be established to mitigate brain damage and improve the prognosis and well-being of these newborn patients. Insulin-like growth factor 1 (IGF-1) is a well-known neurotrophic factor, essential for the survival and functional maturation of immature neurons. This study demonstrated that subcutaneous administration of IGF-1 at 24 and 48 hours of recovery significantly reduced hypoxia-ischemia-induced injury to immature rat brains and improved long-term memory and cognitive behavior. IGF-1's therapeutic effects likely involve its ability to prevent delayed apoptosis, as we demonstrated in primary cortical neuronal cultures under oxygen and glucose deprivation. IGF-1's neuroprotective effects parallel the activities of phosphatidylinositol-3/Akt and its down-stream signaling pathway, suggesting a potential mechanistic link. Overall, evidence from this investigation strongly supports IGF-1's potential therapeutic use in the treatment of hypoxic-ischemic encephalopathy in newborn patients.

Molecular architecture of myelinated peripheral nerves is supported by calorie restriction with aging.

Peripheral nerves from aged animals exhibit features of degeneration, including marked fiber loss, morphological irregularities in myelinated axons and notable reduction in the expression of myelin proteins. To investigate how protein homeostatic mechanisms change with age within the peripheral nervous system, we isolated Schwann cells from the sciatic nerves of young and old rats. The responsiveness of cells from aged nerves to stress stimuli is weakened, which in part may account for the observed age-associated alterations in glial and axonal proteins in vivo. Although calorie restriction is known to slow the aging process in the central nervous system, its influence on peripheral nerves has not been investigated in detail. To determine if dietary restriction is beneficial for peripheral nerve health and glial function, we studied sciatic nerves from rats of four distinct ages (8, 18, 29 and 38 months) kept on an ad libitum (AL) or a 40% calorie restricted diet. Age-associated reduction in the expression of the major myelin proteins and widening of the nodes of Ranvier are attenuated by the dietary intervention, which is paralleled with the maintenance of a differentiated Schwann cell phenotype. The improvements in nerve architecture with diet restriction, in part, are underlined by sustained expression of protein chaperones and markers of the autophagy-lysosomal pathway. Together, the in vitro and in vivo results suggest that there might be an age-limit by which dietary intervention needs to be initiated to elicit a beneficial response on peripheral nerve health.

IGF-I improved bone mineral density and body composition of weaver mutant mice.

Our recent report on a parallel decrease in the body weights and serum IGF-I levels of weaver mice suggests that IGF-I's endocrine function may be impaired in neurodegenerative diseases. To further understand the overall effects of IGF-I deficiency on the postnatal growth, we measured bone mineral density (BMD), bone mineral content (BMC), lean body mass (LBM) and fat mass in male and female weaver mice and wild-type littermates on D21 (prepuberty), D45 (puberty), and D60 (postpuberty) using dual-energy X-ray absorptiometry (DEXA). In both male and female weaver mice, we found that the levels of circulating IGF-I paralleled those of BMD, BMC, and LBM, but not the fat mass. Male weaver mice have normal fat mass at all three ages studied, whereas female weaver mice showed a trend to increase their fat mass as they mature. To determine whether circulating IGF-I is a determinant of body composition, we crossbred IGF-I transgenic mice with homozygous weaver mice, which resulted in a significant increase in circulating IGF-I levels in both male and female weaver mice and normalization of their BMD, BMC and body weights. In summary, our results demonstrated that normal circulating IGF-I levels are important in maintaining BMD, BMC, and body composition in neurodegenerative diseases, such as hereditary cerebellar ataxia.