Normal Mouse Strains Research Articles

Basic Science and Pathogenesis - Part 2.

The Immunoproteasome is a dynamic system found in microglia that is induced under inflammatory conditions and previously hypothesized to be causative of neurodegenerative disorders like Alzheimer's Disease. Mice with immunoproteasome deficiency (LMPPS) and mice with intact immunoproteasome (PS19) were analyzed for AD progression through total tau aggregation and microglia activity. Primary microglia were extracted from normal and LMPKO mouse strains and their total engulfment of tau-aggregate containing cells were compared. LMPPS mice had significantly higher mean aggregation of tau compared to PS19 mice. LMPPS mice also showed a significantly increased activation of microglia and a slightly increased number of total microglia compared to PS19 mice. In-vitro results showed increased total engulfment of tau-aggregate containing cells for LMPKO microglia but statistically insignificant difference when comparing proportion of engulfing microglia. To our knowledge, our results are the first to show that the immunoproteasome is neuroprotective against tauopathies like Alzheimer's Disease in mice.

Genetics but not intestinal microbiota determines the onset of systemic autoimmune disease in BXD2 mice

Abstract The onset and severity of autoimmunity can be attributed to both genetic predisposition and environmental triggers including intestinal microbiota dysbiosis. To determine if development of spontaneous autoimmunity is dependent on gut microbiota, we generated germ-free (GF) BXD2 lupus mice which otherwise develop spontaneous germinal centers (GCs) and high titers of serum autoantibodies. The microbiome and immune phenotypes in specific pathogen free (SPF) and GF BXD2 and normal B6 strains of mice were analyzed. The GF status was confirmed by gut bacterial culture. Surprisingly, the GF status did not affect disease onset and severity in 6-mo-old mice. There were comparable serum levels of IgG or IgM autoantibodies against lupus autoantigens (DNA, histone, and RNP) in SPF versus GF BXD2 mice. Flow cytometry analysis showed that the frequency and absolute numbers of GC B cells, CD4+ T cells, follicular T-helper (Tfh) cells in the spleen were also indistinguishable between SPF and GF BXD2 mice although GF BXD2 mice exhibited a higher number of CD19+ B cells and Tregs, compared to the SPF counterpart. Histologic examination of kidney and lung also showed similar disease scores between SPF and GF BXD2 mice. At older age (12-mo-old), however, there were diminished GC B cells and serum levels of autoantibodies in GF BXD2 mice compared to SPF mice. The results suggest a model in which genetic factors play a dominant role in determining the onset and susceptibility of autoimmunity and that endogenous self-antigens are the primary driver of autoreactive T and B cells leading to spontaneous GCs in BXD2 mice. In contrast, environmental factors such as gut microbiomes may play a modifying role in regulating the persistence of systemic autoimmunity.

Overcoming CD19 Antigen Loss in B-Cell Malignancies with CAR T Cells Targeting BAFF-R

Background: The current success in treating hematological malignancies with CD19 targeted chimeric antigen receptor (CAR) T cells is diminished by tumor relapse from target antigen loss. The B-cell activating factor-receptor (BAFF-R), a tumor necrosis factor receptor superfamily protein (TNFRSF13C), is a particularly interesting alternative target in CD19 relapsed disease and in B cell malignancies in general. BAFF-R null mice exhibit greatly reduced normal B-cell numbers and mouse strains expressing a mutant BAFF-R exhibited decreased B-cell life spans and a dramatically reduced peripheral B-cell compartment. Thus, BAFF-R signaling is a driver of B-cell survival, which may limit the capacity of clonal B-cell tumors to escape therapy by down-regulation of antigen expression. We have exploited the potential of the BAFF/BAFF-R axis and developed a proprietary BAFF-R targeting CAR T cell using a single-chain variable fragment (scFv) of a humanized anti-human BAFF-R antibody engineered into a second generation CAR construct containing 4-1BB costimulatory and CD3ζ intracellular signaling domains (Qin et al. Sci. Transl. Med., In Press). BAFF-R CAR T cells were cytotoxic against a panel of human leukemia and lymphoma lines. Adoptively transferred BAFF-R-CAR T cells eradicated 10-day pre-established tumor xenografts after a single treatment and retained efficacy against xenografts deficient in CD19 expression, including CD19-negative variants within a background of CD19-positive lymphoma cells. BAFF-R-, but not CD19-CAR T cells, also demonstrated antitumor effects against an additional CD19 antigen loss primary patient-derived xenograft (PDX) in vivo. Methods and Results: A first-in-human clinical trial of this BAFF-R CAR T cell in B-ALL is planned. To this end, we cloned the BAFF-R CAR construct into a previously FDA approved clinical lentiviral vector (Figure, part A), and produced BAFF-R CAR T cells using both the research prototype and clinical vectors for head-to-head analysis. We observed comparable cytotoxic T lymphocyte activity against previously established leukemia and lymphoma models in vitro. In vivo, NSG mice challenged with Nalm-6 human B-ALL tumors were randomized (n=5/group) for treatment with either BAFF-R CAR produced from the research prototype or clinical vectors. The two experimental groups were indistinguishable in their antitumor efficacy (data not shown). Further, to advance IND enabling studies we also compared clinical CAR T cell manufacturing strategies. We used an early stage TN/MEM subset for CAR T cell production, as used in previous CAR T cell trials at our institution, and using TN/MEM isolated from healthy donor PBMCs achieved 36% transduction efficiency, comparable to clinical experience at City of Hope. Finally, we assessed the therapeutic effects of BAFF-R CAR TN/MEM cells in vivo. We challenged NSG mice on day 0 with 1 x 105 Nalm-6-CD19 deficient (Nalm-6-CD19KO) human ALL tumor cells and randomized them (n=5/group) to receive a single infusion of either low dose (1 x 106) or high dose (2 x 106) BAFF-R-CAR TN/MEM cells on day 10. Because transduction efficiency was 36%, 2.8 or 5.6 x 106 total T cells were infused to yield 1 or 2 x106 BAFF-R-CAR TN/MEM, respectively. Non-transduced T cells from the same donor were used as allogeneic controls (non-CAR). Tumors were monitored by bioluminescent imaging on the days indicated. Both the low and the high dose BAFF-R CAR T cell groups demonstrated complete Nalm-6 CD19KO tumor regressions, compared with controls (Figure, part B). Conclusions: Our studies support the clinical development of BAFF-R CAR T cells and a pending clinical trial of BAFF-R CAR T cell therapy in relapsed/refractory B-ALL patients who have failed prior CD19-targeted immunotherapy. Targeting BAFF-R may thereby add to existing alternative strategies to overcome relapse from CD19 antigen loss. While BAFF-R antigen loss by tumor cells is unlikely, because its expression is critically required for normal B-cell survival, this hypothesis can only be established by clinical testing. Disclosures Qin: InnoLifes: Consultancy, Equity Ownership; Pepromene Bio: Consultancy, Equity Ownership. Aldoss:AUTO1: Consultancy; Helocyte: Consultancy, Honoraria, Other: travel/accommodation/expenses; Jazz Pharmaceuticals: Honoraria, Other: travel/accommodation/expenses, Speakers Bureau; Agios: Consultancy, Honoraria. Kwak:Pepromene Bio: Consultancy, Equity Ownership, Research Funding; InnoLifes: Consultancy, Equity Ownership; Xeme BioPharma, Inc: Consultancy, Equity Ownership; Enzychem LifeSciences: Consultancy; Celltrion, Inc.: Consultancy; Celltrion Healthcare: Consultancy.

Crisp1 and alopecia areata in C3H/HeJ mice

Alopecia areata (AA), a cell mediated autoimmune disease, is the second most common form of hair loss in humans. While the autoimmune disease is responsible for the underlying pathogenesis, the alopecia phenotype is ultimately due to hair shaft fragility and breakage associated with structural deficits. Quantitative trait genetic analyses using the C3H/HeJ mouse AA model identified cysteine-rich secretory protein 1 (Crisp1), a hair shaft structural protein, as a candidate gene within the major AA locus. Crisp1 transcripts in the skin at various times during disease development were barely detectable. In situ hybridization identified Crisp1 expression within the medulla of hair shafts from clinically normal strains of mice but not C3H/HeJ mice with AA. Follow-up work with 5-day-old C3H/HeJ mice with normal hair also had essentially no expression of Crisp1. Other non-inflammatory based follicular dystrophy mouse models with similar hair shaft abnormalities also have little or no Crisp1 expression. Shotgun proteomics, used to determine strain difference in hair proteins, confirmed that there was very little CRISP1 within normal C3H/HeJ mouse hair in comparison to 11 other strains. However, mutant mice with hair medulla defects also had undetectable levels of CRISP1 in their hair. Crisp1 null mice had normal skin, hair follicles, and hair shafts indicating that the lack of the CRISP1 protein does not translate directly into defects in the hair shaft or hair follicle. These results suggest that CRISP1 may be an important structural component of mouse hair and that its strain-specific dysregulation may indicate a predisposition to hair shaft disease such as AA.

T cell movement into the pancreas based on insulin receptor expression (BA14P.208)

Abstract In the nonobese diabetic (NOD) mouse, type 1 diabetes is an autoimmune disease characterized by insulitis and T cell-mediated beta cell destruction. The importance of insulin receptor (IR) expression in the pathogenesis of diabetes was examined since IR is a chemotactic molecule capable of directing cell movement in response to a gradient of insulin. Our published data shows that T cells, obtained from NOD diabetic mice, expressing a high density of IR can aggressively transfer insulitis and diabetes while T cells with low to negative amounts of IR, are capable of neither. Therefore, IR may function to deliver T cells to the islet where Ag specific cells within the population can recognize and destroy beta cells. Recently, it has been shown in NOD mice that benign insulitis can occur in the absence of T cell-MHC/Ag interactions. The object of this project was to test whether T cells expressing IR, can move into the pancreas based on insulin chemotaxis alone, in normal strains of mice. A transgenic C57Bl/6 mouse was made in which the mouse IR gene with a 3XFLAG tag was placed behind the CD3 promoter and enhancer to target IR expression on all T cells. In this transgenic model there is IR expression on all T cells and with age the transgenic mice exhibit insulitis, but not diabetes. Distinct areas of the IR mediate metabolic or chemotactic signaling indicating that a specific part of the IR may be selectively targeted for therapeutic intervention to block T cell movement.

Acute and Chronic Kudzu Improves Plasma Glucose Tolerance in Non-Diabetic CD-1 Mice.

Previous studies demonstrate that kudzu root extract and its major isoflavone (puerarin) improve glucose metabolism in animal models of insulin resistance and type 2 diabetes; however, these beneficial effects have not been investigated in normal glycemic mice. The present study investigates the effect of acute and chronic kudzu root extract supplementation on glucose tolerance in normoglycemic CD-1 mice. Male, adult CD-1 mice were fed a phytoestrogen-free diet containing 0.2% or 0.0% kudzu root extract for 6 weeks. Thereafter, they were acutely administered kudzu root extract (75 mg/kg BW; oral) or vehicle followed by a glucose challenge (2 g/kg BW; oral). In control fed mice, the acute glucose challenge increased blood glucose ~300% after 30 minutes, and acute kudzu root extract administration significantly blunted this response by ~50%. In mice chronically fed a kudzu-supplemented diet, glucose tolerance was improved, and acute treatment caused no additional improvement. Irrespective of treatment, all mice were normoglycemic at the start of each glucose challenge. Administration of insulin resulted in a larger decrease in blood glucose in chronic kudzu-supplemented compared to control mice. Co-administration of phloridzin (a specific inhibitor of SGLT-mediated glucose uptake), improved glucose tolerance in acutely kudzu-treated mice but had no significant effect on glucose tolerance in chronically treated mice. These results indicate that both acute and chronic administration of kudzu root extract improves glucose tolerance in a normal glycemic mouse strain and that the effects of chronic kudzu feeding may be mediated, in part, by enhanced insulin sensitivity (chronic) and inhibition of sodium dependent glucose transport.

Interaction entre facteurs d’environnement et fonds génétique dans le diabète de type 2

The respective roles of predisposing genetic factors and environmental factors in the development of type 2 diabetes (T2D) in obese subjects is poorly documented. Rodent models have been set up in an attempt to better understand of the differential effect of a prolonged metabolic stress induced by a high fat diet on glycaemic control according to the genetic background. In utero growth retardation resulting from a hypocaloric diet in pregnant rats induces a dramatic alteration of the development of islet cells leading to diabetes and insulin secretory defects in adult age. Experimentally induced diabetes in rodents results in hyperglycaemia and hyperinsulinemia in the fetus related to accelerated endocrine pancreas maturation responsible for the onset of diabetes in the adult. Deranged metabolic environment during fetal life may therefore further contribute to the onset of diabetes in the adult. Normal mouse strains with different genetic backgrounds show a wide range of responses to a high fat diet, with strains resistant to the diet and other more or less sensitive to the diet, the most sensitive exhibiting obesity diabetes and, insulin deficiency. The inability of the β cell to respond to the increased insulin demand related to insulin resistance seems to be pivotal in the pathophysiologic process and a new notion is emerging: "nutritional genetics" which studies the influence of nutrients on gene expression.

Rab3a ablation related changes in morphology of secretory vesicles in major endocrine pancreatic cells, pituitary melanotroph cells and adrenal gland chromaffin cells in mice

In this work we have compared the ultrastructural characteristics of major pancreatic endocrine cells, pituitary melanotrophs and adrenal chromaffin cells in the normal mouse strain (wild type, WT) and mice with a known secretory deficit, the Rab3a knockout strain (Rab3a KO). For this purpose, pancreata, pituitary glands and adrenal glands from the Rab3a KO and from the WT mice were analysed, using conventional transmission electron microscopy (TEM). In order to assess the significance of the presence of Rab3a proteins in the relevant cells, we focused primarily on their secretory vesicle morphology and distribution. Our results showed a comparable general morphology in Rab3a KO and WT in all assessed endocrine cell types. In all studied cell types, the distribution of secretory granules along the plasma membrane (number of docked and almost-docked vesicles) was comparable between Rab3a KO and WT mice. Specific differences were found in the diameters of their secretory vesicles, diameters of their electron-dense cores and the presence of autophagic structures in the cells of Rab3A KO mice only. Occasionally, individual electron-dense round vesicles were present inside autophagosome-like structures; these were possibly secretory vesicles or their remnants. The differences found in the diameters of the secretory vesicles confirm the key role of Rab3a proteins in controlling the balance between secretory vesicle biogenesis and degradation, and suggest that the ablation of this protein probably changes the nature of the reservoir of secretory vesicles available for regulated exocytosis.

Spermatogenic defects in F2 mice between normal mouse strains C3H and C57BL/6 without mutation

Genetic disorders are usually considered to be caused by harmful gene mutations, as well as by chromosomal aberrations, including small insertions, duplications and/or deletions. However, as infertile individuals often arise among the offspring of crosses between two fertile mouse strains, we postulate that a certain combination of 'normal' genes with neither gene mutations nor chromosomal aberrations can cause such serious phenotypic alterations as reproductive dysfunction. In this study, we show evidence that a combination of multiple normal genes from two different normal mouse strains manifests a wide range of male reproductive dysfunctions, from benign changes to complete infertility. These abnormal phenotypes are thought to have occurred by epistatic interactions of alleles.

Cytosolic Carboxypeptidase 1 Is Involved in Processing α- and β-Tubulin

The Purkinje cell degeneration (pcd) mouse has a disruption in the gene encoding cytosolic carboxypeptidase 1 (CCP1). This study tested two proposed functions of CCP1: degradation of intracellular peptides and processing of tubulin. Overexpression (2-3-fold) or knockdown (80-90%) of CCP1 in human embryonic kidney 293T cells (HEK293T) did not affect the levels of most intracellular peptides but altered the levels of α-tubulin lacking two C-terminal amino acids (delta2-tubulin) ≥ 5-fold, suggesting that tubulin processing is the primary function of CCP1, not peptide degradation. Purified CCP1 produced delta2-tubulin from purified porcine brain α-tubulin or polymerized HEK293T microtubules. In addition, CCP1 removed Glu residues from the polyglutamyl side chains of porcine brain α- and β-tubulin and also generated a form of α-tubulin with two C-terminal Glu residues removed (delta3-tubulin). Consistent with this, pcd mouse brain showed hyperglutamylation of both α- and β-tubulin. The hyperglutamylation of α- and β-tubulin and subsequent death of Purkinje cells in pcd mice was counteracted by the knock-out of the gene encoding tubulin tyrosine ligase-like-1, indicating that this enzyme hyperglutamylates α- and β-tubulin. Taken together, these results demonstrate a role for CCP1 in the processing of Glu residues from β- as well as α-tubulin in vitro and in vivo.

Obesity‐Induced Diabetes in Mouse Strains Treated With Gold Thioglucose: A Novel Animal Model for Studying β‐Cell Dysfunction

An obesity-induced diabetes model using genetically normal mouse strains would be invaluable but remains to be established. One reason is that several normal mouse strains are resistant to high-fat diet-induced obesity. In the present study, we show the effectiveness of gold thioglucose (GTG) in inducing hyperphagia and severe obesity in mice, and demonstrate the development of obesity-induced diabetes in genetically normal mouse strains. GTG treated DBA/2, C57BLKs, and BDF1 mice gained weight rapidly and exhibited significant increases in nonfasting plasma glucose levels 8-12 weeks after GTG treatment. These mice showed significantly impaired insulin secretion, particularly in the early phase after glucose load, and reduced insulin content in pancreatic islets. Interestingly, GTG treated C57BL/6 mice did not become diabetic and retained normal early insulin secretion and islet insulin content despite being as severely obese and insulin resistant as the other mice. These results suggest that the pathogenesis of obesity-induced diabetes in GTG-treated mice is attributable to the inability of their pancreatic β-cells to secrete enough insulin to compensate for insulin resistance. Mice developing obesity-induced diabetes after GTG treatment might be a valuable tool for investigating obesity-induced diabetes. Furthermore, comparing the genetic backgrounds of mice with different susceptibilities to diabetes may lead to the identification of novel genetic factors influencing the ability of pancreatic β-cells to secrete insulin.

New approaches to rewarding pharmaceutical innovation

The onset and severity of autoimmunity can be attributed to both genetic predisposition and environmental triggers including intestinal microbiota dysbiosis. To determine if development of spontaneous autoimmunity is dependent on gut microbiota, we generated germ-free (GF) BXD2 lupus mice which otherwise develop spontaneous germinal centers (GCs) and high titers of serum autoantibodies. The microbiome and immune phenotypes in specific pathogen free (SPF) and GF BXD2 and normal B6 strains of mice were analyzed. The GF status was confirmed by gut bacterial culture. Surprisingly, the GF status did not affect disease onset and severity in 6-mo-old mice. There were comparable serum levels of IgG or IgM autoantibodies against lupus autoantigens (DNA, histone, and RNP) in SPF versus GF BXD2 mice. Flow cytometry analysis showed that the frequency and absolute numbers of GC B cells, CD4⁺ T cells, follicular T-helper (Tfh) cells in the spleen were also indistinguishable between SPF and GF BXD2 mice although GF BXD2 mice exhibited a higher number of CD19⁺ B cells and Tregs, compared to the SPF counterpart. Histologic examination of kidney and lung also showed similar disease scores between SPF and GF BXD2 mice. At older age (12-mo-old), however, there were diminished GC B cells and serum levels of autoantibodies in GF BXD2 mice compared to SPF mice. The results suggest a model in which genetic factors play a dominant role in determining the onset and susceptibility of autoimmunity and that endogenous self-antigens are the primary driver of autoreactive T and B cells leading to spontaneous GCs in BXD2 mice. In contrast, environmental factors such as gut microbiomes may play a modifying role in regulating the persistence of systemic autoimmunity.

A growth stimulus is needed for IGF-1 to induce skeletal muscle hypertrophy in vivo

Here, we characterise new strains of normal and dystrophic (mdx) mice that overexpress Class 2 IGF-1 Ea in skeletal myofibres. We show that transgenic mice have increased muscle levels of IGF-1 (approximately 13-26 fold) and show striking muscle hypertrophy (approximately 24-56% increase in mass). Adult normal muscles were resistant to elevated IGF-1; they reached adult steady state and maintained the same mass from 3 to 12 months. By contrast, dystrophic muscles from mdx/IGF-1(C2:Ea) mice continued to increase in mass during adulthood. IGF-1 signalling was evident only in muscles that were growing as a result of normal postnatal development (23-day-old mice) or regenerating in response to endogenous necrosis (adult mdx mice). Increased phosphorylation of Akt at Ser473 was not evident in fasted normal adult transgenic muscles, but was 1.9-fold higher in fasted normal young transgenic muscles compared with age-matched wild-type controls and fourfold higher in fasted adult mdx/IGF-1(C2:Ea) compared with mdx muscles. Muscles of adult mdx/IGF-1(C2:Ea) mice showed higher p70(S6K)(Thr421/Ser424) phosphorylation and both young transgenic and adult mdx/IGF-1(C2:Ea) mice had higher phosphorylation of rpS6(Ser235/236). The level of mRNA encoding myogenin was increased in normal young (but not adult) transgenic muscles, indicating enhanced myogenic differentiation. These data demonstrate that elevated IGF-1 has a hypertrophic effect on skeletal muscle only in growth situations.

Autoimmunity during Thymectomy-Induced Lymphopenia: Role of Thymus Ablation and Initial Effector T Cell Activation Timing in Nonobese Diabetic Mice

Autoimmune diseases develop in selected normal mouse strains when thymectomy (Tx) is performed at 3 days of age (d3-Tx). Insufficient T cell regulation after Tx may result from a defect in regulatory T (Treg) cells or from an augmented effector T (Teff) cell number/pathogenicity. We have previously shown that Tx at 3 wk (wk3-Tx), the age of massive islet Ag release, accelerates diabetes onset. We now have determined diabetes incidence in d3-Tx nonobese diabetic mice and compared the frequency and function of their Teff and Treg cells with those of wk3-Tx mice. We found that d3-Tx had no effect on diabetes incidence, but induced gastritis. After day 3 and week 3 Tx, Treg cells were fully competent and their frequency increased. The number of diabetogenic T cells was greatly amplified after wk3-Tx and likely overcame Treg cell control, leading to an early tolerance breakdown. By contrast, in d3-Tx mice, activation concerned few cells and Teff cell amplification remained controlled. This suggests that Tx enhances autoimmunity when it coincides with the first encounter of autoreactive T cells with their cognate Ag. The relationship between Tx-induced lymphopenia, tissue remodeling, and autoimmunity is discussed.

Purkinje cell axonal torpedoes are unrelated to advanced aging and likely reflect cerebellar injury

Torpedoes, swellings of the proximal Purkinje cell axon, are thought to represent a cellular response to injury [3]. They may occur in a variety of cerebellar disorders [7]. Most recently, their numbers were noted to be six-times higher in essential tremor (ET) than control brains [4]. Torpedoes are also often viewed as a cumulative phenomenon associated with advanced aging [3,4], yet there are surprisingly few supporting data. We quantified torpedoes in normal human cerebella spanning a considerable age range to assess whether torpedoes are a cumulative phenomenon of aging. These data help place the relative abundance of torpedoes in ET in context. Control brains at the New York Brain Bank, Columbia University Medical Center (CUMC) had been controls in the Alzheimer’s Disease Research Center or non-neurologic patients at CUMC. Each had a complete neuropathologic assessment [4] including Braak AD stage [2] and CERAD [5] for Alzheimer’s tangle and plaque pathologies. As documented [4], a standard 3 × 20 × 25 mm parasagittal tissue block was harvested from each neocerebellum (N = 48) and immersion-fixed in 10% buffered formalin. Paraffin sections (7 μm thick) were stained with Luxol Fast Blue counterstained with Hematoxylin and Eosin (LH&E) [4]. Torpedoes (Figure 1) in one entire LH&E section were counted blinded to age. Purkinje cells in five randomly-selected 100x LH&E stained fields of the standard cerebellar section were counted and the mean reported. In 32 brains, a second set of sections from the same blocks were used as replicate data. Figure 1 Control cerebellar tissue showing a torpedo (arrow). LH&E 400x magnification. Non-parametric tests (Spearman’s r, Mann Whitney test, Kruskal Wallis test) were used. Because of zero values (0 torpedoes), in linear regression analyses, log10(torpedoes +1) was the dependent variable and age, the independent variable. Age at death ranged from 6–93 years. Mean±SD (median, range) number of torpedoes = 1.8±2.1 (1, 0–11)(Table). Table Clinical characteristics/postmortem features (48 controls) Number of torpedoes was correlated with age at death (r = 0.35, p = 0.02, Table), but not when the brains in the youngest age quartile (≤36 years) were excluded (i.e., in brains with age of death ranging from 37–93 years, r = −0.03, p = 0.85). While (mean±SD, median) number of torpedoes was low in brains in the youngest quartile (quartile 1, ≤36 years, 0.5±0.9, 0), it did not differ among brains in the remaining 3 quartiles: quartile 2 (37–63 years) 1.9±1.6, 1.5; quartile 3 (64–80 years) 2.9±3.2, 2; quartile 4 (≥81 years) 2.0±1.4, 1.5 (for comparison of quartiles 2–4, p = 0.88)(Figure 2). Figure 2 Number of torpedoes (Y axis) by age at death quartile (X axis). In a linear regression analysis, log-transformed number of torpedoes was associated with age (beta 0.004, p = 0.01) but not in a fully adjusted model including gender, race, postmortem interval (PMI), brain weight, number of Purkinje cells, CERAD plaque score and Braak stage(beta for age −0.003, p = 0.71). In unadjusted and adjusted models restricted to age quartiles 2–4, beta = −0.001, p = 0.70 and beta = −0.003 and p = 0.69, respectively. The results of replicate analyses on 32 brains were similar to our primary analyses. The number of torpedoes was lowest in the youngest age quartile (0.2±0.4, 0) but was similar in the remaining three age quartiles (quartile 2: 1.8±1.9, 2; quartile 3: 3.2±2.3, 3.5; quartile 4: 2.7±2.4, 2.5)(for comparison of quartiles 2–4, p = 0.82). We examined control brains spanning a wide age range. Torpedoes were rare in the first four decades of life, but thereafter, there was no aging-associated increase. Torpedoes have been commented on as rare incidental findings in normal human control brains, although it has not been demonstrated that they are more abundant as a function of advanced age. One study [3] examined 32 axons in three normal individuals (ages 64, 70, 86). The 86 year old had two torpedoes. In a study of two normal mouse strains (age 8 days - 32 months)[1], <0.1% of Purkinje cells had torpedoes at 6 months; this increased linearly to 13.7% by age 32 months [1]. However, in a study of other normal mice strains, torpedoes were absent, suggesting that torpedoes are not a “simple aging phenomena” [6]. The lack of an association here between these lesions and advanced aging suggests that the abundance of these lesions in ET is a marker of cerebellar injury and not merely representative of accelerated aging.

Cell-Phone Radiation and Cancer Studies in Normal Mice [Telecommunications Health & Safety

This article discusses laboratory studies using four different strains of normal mice. For exposures of one year or less, experiments with three strains of mice did not show a promotional or co-carcinogenic effect on tumorigenesis. The two-year study with female and male B6C3F1 mice showed that while exposure to GSM-900 fields did not produce an overall increase in the incidence of tumors, there was a dose-dependent decrease in the number of tumor-bearing males, and more so for the incidence of hepatocellular carcinomas.

The difference in gliosis induced by β-amyloid and Tau treatments in astrocyte cultures derived from senescence accelerated and normal mouse strains

Astrocytes react to various neurodegenerative insults rapidly and undergo changes known as gliosis or astrogliosis. In Alzheimer's disease (AD), a wall of reactive astrocytes surrounds senile plaques of β-amyloid (Aβ) and might play an important role in clearing of Aβ. AD is neuropathologically characterized by the co-existence of two pathological structures, senile plaques and neurofibrillary tangles composed of Aβ and Tau protein respectively. However, the molecular mechanisms underlie astrogliosis and increased expressions of GFAP and other astrogliosis markers are poorly understood. Since AD is age related, the aim of this study is to compare the gliosis of aging prone astrocytes cultured from senescence-accelerated mice and astrocytes from normal mice in response to Aβ and Tau treatment. Our results demonstrated that the aging prone astrocytes have showed larger degree of gliosis than normal astrocytes. Since reactive astrocytes had less ability to support co-cultured neurons as compared with control astrocytes. Therefore, it is likely that aging prone astrocytes might contribute to cell loss or dysfunction associated with insults in AD. In other words, aging prone astrocytes might have decreased ability than normal astrocytes to protect or prevent neuronal dysfunction in AD pathology. In addition, further AD related studies should use aging prone astrocytes instead of normal astrocytes.

High Affinity Glycosaminoglycan and Autoantigen Interaction Explains Joint Specificity in a Mouse Model of Rheumatoid Arthritis

In the K/BxN mouse model of rheumatoid arthritis, autoantibodies specific for glucose-6-phosphate isomerase (GPI) can transfer joint-specific inflammation to most strains of normal mice. Binding of GPI and autoantibody to the joint surface is a prerequisite for joint-specific inflammation. However, how GPI localizes to the joint remains unclear. We show that glycosaminoglycans (GAGs) are the high affinity (83 nm) joint receptors for GPI. The binding affinity and structural differences between mouse paw/ankle GAGs and elbows/knee GAGs correlated with the distal to proximal disease severity in these joints. We found that cartilage surface GPI binding was greatly reduced by either chondroitinase ABC or beta-glucuronidase treatment. We also identified several inhibitors that inhibit both GPI/GAG interaction and GPI enzymatic activities, which suggests that the GPI GAG-binding domain overlaps with the active site of GPI enzyme. Our studies raise the possibility that GAGs are the receptors for other autoantigens involved in joint-specific inflammatory responses.

Widespread natural variation in murine natural killer T‐cell number and function

Natural killer T (NKT) cells comprise a novel T-lymphocyte subset that can influence a wide variety of immune responses through their ability to secrete large amounts of a variety of cytokines. Although variation in NKT-cell number and function has been extensively studied in autoimmune disease-prone mice, in which it has been linked to disease susceptibility, relatively little is known of the natural variation of NKT-cell number and function among normal inbred mouse strains. Here, we demonstrate strain-dependent variation in the susceptibility of C57BL/6J and BALB/cJ mice to NKT-mediated airway hyperreactivity, which correlated with significant increases in serum interleukin-4 (IL-4) and IL-13 elicited by the synthetic glycosphingolipid alpha-galactosylceramide. Examination of NKT-cell function revealed a significantly greater frequency of cytokine-producing NKT cells in C57BL/6J versus BALB/cJ mice as well as significant differences in the kinetics of NKT-cell cytokine production. Extension of this analysis to a panel of inbred mouse strains indicated that variability in NKT-cell cytokine production was widespread. Similarly, an examination of NKT-cell frequency revealed a significantly greater number of liver NKT cells in the C57BL/6J mice versus BALB/cJ mouse livers. Again, examination of a panel of inbred mouse strains revealed that liver NKT-cell numbers were quite variable, spanning over a 100-fold range. Taken together, these results demonstrate the presence of widespread natural variation in NKT-cell number and function among common inbred mouse strains, which may have implications for the examination of the influence of NKT cells in immune responses and disease pathogenesis among different genetic backgrounds.

Resveratrol Delays Age-Related Deterioration and Mimics Transcriptional Aspects of Dietary Restriction without Extending Life Span

A small molecule that safely mimics the ability of dietary restriction (DR) to delay age-related diseases in laboratory animals is greatly sought after. We and others have shown that resveratrol mimics effects of DR in lower organisms. In mice, we find that resveratrol induces gene expression patterns in multiple tissues that parallel those induced by DR and every-other-day feeding. Moreover, resveratrol-fed elderly mice show a marked reduction in signs of aging, including reduced albuminuria, decreased inflammation, and apoptosis in the vascular endothelium, increased aortic elasticity, greater motor coordination, reduced cataract formation, and preserved bone mineral density. However, mice fed a standard diet did not live longer when treated with resveratrol beginning at 12 months of age. Our findings indicate that resveratrol treatment has a range of beneficial effects in mice but does not increase the longevity of ad libitum-fed animals when started midlife.