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Inefficiency in GM2 ganglioside elimination by human lysosomal beta-hexosaminidase beta-subunit gene transfer to fibroblastic cell line derived from Sandhoff disease model mice.

Sandhoff disease (SD) is an autosomal recessive GM2 gangliosidosis caused by the defect of lysosomal beta-hexosaminidase (Hex) beta-subunit gene associated with neurosomatic manifestations. Therapeutic effects of Hex subunit gene transduction have been examined on Sandhoff disease model mice (SD mice) produced by the allelic disruption of Hexb gene encoding the murine beta-subunit. We demonstrate here that elimination of GM2 ganglioside (GM2) accumulated in the fibroblastic cell line derived from SD mice (FSD) did not occur when the HEXB gene only was transfected. In contrast, a significant increase in the HexB (betabeta homodimer) activity toward neutral substrates, including GA2 (asialo-GM2) and oligosaccharides carrying the terminal N-acetylglucosamine residues at their non-reducing ends (GlcNAc-oligosaccharides) was observed. Immunoblotting with anti-human HexA (alphabeta heterodimer) serum after native polyacrylamide gel electrophoresis (Native-PAGE) revealed that the human HEXB gene product could hardly form the chimeric HexA through associating with the murine alpha-subunit. However, co-introduction of the HEXA encoding the human alpha-subunit and HEXB genes caused significant corrective effect on the GM2 degradation by producing the human HexA. These results indicate that the recombinant human HexA could interspeciesly associate with the murine GM2 activator protein to degrade GM2 accumulated in the FSD cells. Thus, therapeutic effects of the recombinant human HexA isozyme but not human HEXB gene product could be evaluated by using the SD mice.

Animals↗

Validation of two reference genes for mRNA level studies of murine disease models in neurobiology.

Reverse transcription of extracted cellular RNA combined with real-time PCR is now an established method for sensitive detection and quantification of specific mRNA level changes in experimental models of neurological diseases. To neutralize the impact of experimental error and make quantification more precise, normalization of test gene data using data from a constantly expressed gene, a reference gene that is tested along with the test gene, is required. There is no single gene constantly expressed under all experimental conditions. For a given set of conditions or a given disease model, identification of an unaffected reference gene is necessary. In this report, we present our findings from evaluation and validation of the genes encoding hypoxanthine guanine phosphoribosyl transferase 1 (HPRT1) and glyceraldehyde phosphate dehydrogenase (GAPDH) as individual reference genes in mRNA level studies involving four murine neurological disease models. We find both genes are suitable as a reference gene with these four models, provided quantification of subtle changes are avoided. We furthermore demonstrate that above a certain threshold of test mRNA level changes and given high quality RNA processing, normalization to total RNA alone provides for equally reliable quantitative mRNA level results.

Animals↗

Polycystic kidney disease: genes, proteins, animal models, disease mechanisms and therapeutic opportunities.

An increased understanding of the genetic, molecular and cellular mechanisms responsible for the development of polycystic kidney disease has laid out the foundation for the development of rational therapies. Many animal models where these therapies can be tested are currently available. This review summarizes the rationale for these treatments, the results of preclinical trials and the prospects for clinical trials, some already in early phases of implementation.

Animals↗

A Landscape of Drosophila melanogaster Disease Models: From Genetic Platforms to Cross-Disease Mechanisms and Translational Research.

Modeling human diseases using the fruit fly (Drosophila melanogaster) has established itself as a cornerstone of functional genomics and preclinical medicine. Despite its anatomical simplicity, the Drosophila genome shares remarkable functional conservation with human disease-related genes, enabling the study of complex physiological traits through accessible tissue models. Furthermore, beyond individual disease models, we propose a framework demonstrating how these diseases converge at common molecular centers, such as the breakdown of protein homeostasis, mitochondrial dysfunction, chronic inflammation, and organ-to-organ communication. Finally, we discuss strategies for integrating the Drosophila platform into drug development pipelines and establishing standards to enhance inter-laboratory reproducibility. Overall, this review highlights the enduring value of fruit flies as a model system, particularly when combined with AI-omics approaches to transform complex biological datasets into actionable therapeutic strategies.

Drosophila↗

Disease model: LAMP-2 enlightens Danon disease.

Danon disease ('lysosomal glycogen storage disease with normal acid maltase') is characterized by a cardiomyopathy, myopathy and variable mental retardation. Mutations in the coding sequence of the lysosomal-associated membrane protein 2 (LAMP-2) were shown to cause a LAMP-2 deficiency in patients with Danon disease. LAMP-2 deficient mice manifest a similar vacuolar cardioskeletal myopathy. In addition to the patient reports LAMP-2 deficiency in mice causes pancreatic, hepatocytic, endothelial and leucocyte vacuolation. LAMP-2 deficient mice represent a valuable animal model of Danon disease. They will further be used to study the exact role of LAMP-2 in autophagy and to analyse the consequences of an impaired autophagic pathway in various tissues.

Animals↗

Use of autoantigen-knockout mice in developing an active autoimmune disease model for pemphigus.

The development of experimental models of active autoimmune diseases can be difficult due to tolerance of autoantigens, but knockout mice, which fail to acquire tolerance to the defective gene product, provide a useful tool for this purpose. Using knockout mice lacking desmoglein 3 (Dsg3), the target antigen of pemphigus vulgaris (PV), we have generated an active disease model for this autoantibody-mediated disease. Dsg3(-/-) mice, but not Dsg3(+/-) littermates, produced anti-Dsg3 IgG that binds native Dsg3, when immunized with recombinant mouse Dsg3. Splenocytes from the immunized Dsg3(-/-) mice were then adoptively transferred into Rag-2(-/-) immunodeficient mice expressing Dsg3. Anti-Dsg3 IgG was stably produced in the recipient mice for more than 6 months without further boosting. This IgG bound to Dsg3 in vivo and disrupted the cell-cell adhesion of keratinocytes. Consequently, the recipient mice developed erosions in their oral mucous membranes with typical histologic findings of PV. In addition, the recipient mice showed telogen hair loss, as found in Dsg3(-/-) mice. Collectively, the recipient mice developed the phenotype of PV due to the pathogenic anti-Dsg3 IgG. This model will be valuable for developing novel therapeutic strategies. Furthermore, our approach can be applied broadly for the development of various autoimmune disease models.

Animals↗

CD4+CD25+ regulatory T cells: II. Origin, disease models and clinical aspects.

Autoimmune diseases afflict approximately 5% of the population and reflect a failure in the immune system to discriminate between self and non-self resulting in the breakdown of self-tolerance. Regulatory CD4+CD25+ T cells (Treg cells) have been shown to play an important role in the maintenance of immune homeostasis and self-tolerance by counteracting the development and effector functions of potentially autoreactive T cells. We have in the previous APMIS review described the phenotype and physiology of Treg cells. The present overview deals with the thymic origin of Treg cells and their role in disease models such as autoimmune gastritis and inflammatory bowel disease. Finally, we will consider some aspects of the therapeutic potential of Treg cells.

Animals↗

A pharmacokinetic-pharmacodynamic disease model to predict in vivo antiviral activity of maraviroc.

BACKGROUND: The viral dynamics of human immunodeficiency virus (HIV) infection has been widely studied and expressed as mathematic equations. For most of the current registered antiretroviral drugs, the pharmacokinetics is well characterized and some relationships with the viral load-time profiles in plasma from HIV patients have been established. The integration of these models in a pharmacokinetic (PK)-pharmacodynamic (PD)-disease model can help toward a better understanding of the complexity of the interactions, as well as in the identification and clarification of the current model assumptions. METHODS: This work describes the development of a generic PK-PD disease model for a short-term (10 days) monotherapy phase IIa study with a novel anti-HIV drug, maraviroc (UK-427,857). The disease component of the model was based on the model published by Bonhoeffer et al, which was adapted for short-term treatment and for the new mechanism of action, CCR5-receptor antagonism. The model parameters were derived from the literature, as well as from a model-based analysis of available phase IIa clinical data from another investigational antiretroviral drug. The PD component that links the plasma concentrations of maraviroc to the inhibition of virus replication was based on in vitro measurements of drug potency and took into account the difference in the in vitro and in vivo protein binding and the uncertainties regarding the interpretation of the in vitro to in vivo extrapolation of the 50% inhibitory concentration. Finally, the PK component was based on information obtained from a single-dose study in healthy volunteers. RESULTS: The integrated PK-PD disease modeling allowed prediction of the effect on viral load of different maraviroc doses given as monotherapy to drug-naive patients. CONCLUSIONS: By making use of the available PK-PD disease model, the possible range of active oral doses for maraviroc in HIV-positive patients was estimated by simulation before any clinical trials were taking place. The use of a model-based approach for selecting doses for clinical phase IIa has improved and accelerated the drug's development. This model was a powerful tool for assisting in the design of clinical studies on new agents for treating HIV/acquired immunodeficiency syndrome.

Adult↗

Standardization of an experimental disease model of Streptococcus zooepidemicus in the equine.

A reproducible experimental disease model in horses using Streptococcus zooepidemicus was developed. An intravenous challenge dose of 1 X 10(10) colony-forming units (CFU), followed 24 h later with another challenge of 1 X 10(8) CFU of Strep. zooepidemicus produced the desired disease model. The disease was characterized by depression, pyrexia, anorexia, abnormal lung sounds, inflammation of joints, moderate to severe lameness, gradual loss of condition and emaciation. The effects of the disease on hematology, serum chemical profile and different protein fractions were studied. The disease state had no effect on serum glucose, sodium, potassium, chloride, urea nitrogen, creatinine, uric acid, calcium, phosphorus and enzymes SGOT or SGPT. However, the alkaline phosphatase showed a gradual decline. The serum iron levels dropped markedly and remained low to the last day of observations (post-infection day, PID 13). On serum protein electrophoresis, the albumin showed a gradual decrease; whereas, alpha II, beta and gamma globulin levels rose suggesting an immune response. The elevation of rectal temperatures and white blood cell counts related well with clinical observations. The serum iron levels proved very helpful in predicting the severity of clinical signs and often dropped before the onset of clinical signs and pyrexia.

Animals↗

rAAV-mediated shRNA ameliorated neuropathology in Huntington disease model mouse.

Huntington disease (HD) is a fatal progressive neurodegenerative disorder associated with expansion of a CAG repeat in the first exon of the gene coding the protein huntingtin (htt). Although the feasibility of RNA interference (RNAi)-mediated reduction of htt expression to attenuate HD-associated symptoms is suggested, the effects of post-symptomatic RNAi treatment in the HD model mice have not yet been certified. Here we show the effects of recombinant adeno-associated virus (rAAV)-mediated delivery of RNAi into the HD model mouse striatum after the onset of disease. Neuropathological abnormalities associated with HD, such as insoluble protein accumulation and down-regulation of DARPP-32 expression, were successfully ameliorated by the RNAi transduction. Importantly, neuronal aggregates in the striatum were reduced after RNAi transduction in the animals comparing to those at the time point of RNAi transduction. These results suggest that the direct inhibition of mutant gene expression by rAVV would be promising for post-symptomatic HD therapy.

Adenoviridae↗

Syndromes with genetic instability: model diseases for (skin) cancerogenesis.

Tumorigenesis is a multi-step process in which exogenous and endogenous mutational events lead to accumulation of DNA mutations resulting in loss of cellular growth control. During the last decades knowledge about the molecular mechanisms of DNA mutations and the cellular systems that counteract the degeneration of the genome has increased rapidly. This expansion was driven in part by clinical and molecular investigations of syndromes with genetic in-stability. These syndromes are typically associated with an increased predisposition for tumor formation. They include nucleotide excision repair defective syndromes, mismatch repair defective syndromes, and the chromosome break-age syndromes. These diseases mirror vividly the phenotypic consequences of the failure of important cellular systems for the maintenance of the genomic integrity. They significantly contribute to our understanding of the molecular mechanisms of (skin) carcinogenesis and for the development of preventive and therapeutic anticancer strategies.

Animals↗

Stigma or legitimation? A historical examination of the social potentials of addiction disease models.

This article presents a historical discussion of disease models of opiate addiction in the United States in the twentieth century. First, several approaches to defining disease are discussed. Then, the shifts in formulations of opiate addiction as a disease in the twentieth century in the U.S. are analysed in light of the preceding theoretical discussion. The period before 1920 is described as heterodox, as researchers attempted to develop scientific models of opiate addiction, while various medically legitimate and quasi-legitimate treatment approaches flourished in an unregulated marketplace. After 1920, a stigmatizing disease model of opiate addiction was based on a psychiatric formulation that linked chronic addiction with psychoneurotic deficits in certain individuals. After 1940, this model dominated medical and scientific thinking about opiate addiction for several decades. After 1970, enormous changes in the demographics of drug use forced changes to the prevailing model of addiction. A new focus on behavioral aspects of addiction allowed the creation of a nonstigmatizing Parsonian disease model.

History, 20th Century↗

The new disease model of alcoholism.

The new biopsychosocial disease model of alcoholism is examined from the perspective of recent biologic research. Studies of animal and human genetic predispositions suggest the presence of genetic influences over drinking behavior as well as biologic risk factors related to deficiencies in various neurochemicals. Ethanol affects the fluidity of cell membrane lipids, eventually causing membrane dysfunction. It also adversely affects the activity of two enzymes, monoamine oxidase and adenylate cyclase, that have important functions in the information processing system of the brain. Research on condensation products formed in the brain after alcohol consumption has provided clues to the development of alcoholism, but many questions remain unanswered. Alcoholism is clearly a multidimensional phenomenon in which biologic, psychological, and sociocultural factors interact to produce illness.

Alcoholism↗

Evaluation of scolicidal agents in an experimental hydatid disease model.

INTRODUCTION: The treatment of hydatid disease is largely surgical, with medical treatment being reserved as coadjuvant treatment. The scolicidal agents have been, and are being used mainly during surgical manipulation of the cysts, with the object of avoiding relapses and peritoneal dissemination. OBJECTIVE: Evaluation of the scolicidal agents used in surgery in a hydatid disease model in the mouse. MATERIAL AND METHODS: We have used 85 Swiss OF1 mice, weighing more than 30 g, of 90 +/- 10 days of age, in which a picture of hydatid sowing was reproduced by means of intra-peritoneal inoculation with 0.2 ml of a suspension which contained approximately 1,200 viable protoscolex of Echinococcus granulosus which came from the livers of parasite-infested sheep. 24 h after the inoculation, the mice were subjected to a median laparotomy for the introduction of 1 ml of the scolicidal solution to be evaluated: physiologic saline (n = 10); 10% povidone iodine (n = 15); praziquantel (n = 15); 10% hydrogen peroxide (n = 15); 10% hypertonic saline (n = 15); simulated operation (n = 15). After 7 months of follow-up, the mice were sacrificed and the following was evaluated: number of isolated cysts, cyst masses, and total cysts. RESULTS: The number of isolated cysts which developed was significantly lower in the hydrogen peroxide group (tF 2.14 < RC 3.29). The number of cyst masses was significantly reduced in the hydrogen peroxide group (tF 2.14 < RC 2.18), in the povidone iodine group (tF 2.17 < RC 3), and in the hypertonic saline group (tF 2.11 < RC 2.77). The total number of cysts which developed decreased significantly in the hydrogen peroxide (tF 2.14 < RC 2.84) and the povidone iodine (tF 2.17 < RC 3.79) groups. CONCLUSIONS: Hydrogen peroxide and povidone iodine show a greater protoscolicidal effect than simple cleansing with physiological saline, hypertonic saline, or praziquantel.

Animals↗

Acupuncture prevents 6-hydroxydopamine-induced neuronal death in the nigrostriatal dopaminergic system in the rat Parkinson's disease model.

Parkinson's disease (PD) is a chronic neurodegenerative disorder, and it has been suggested that treatments promoting survival and functional recovery of affected dopaminergic neurons could have a significant and long-term therapeutic value. In the present study, we investigated the neuroprotective effects of acupuncture on the nigrostriatal system in rat unilaterally lesioned with 6-hydroxydopamine (6-OHDA, 4 microg/microl, intrastriatal injection) using tyrosine hydroxylase (TH) and receptor for brain-derived neurotrophic factor, trkB, immunohistochemistries. Two weeks after the lesions were made, rats presented with asymmetry in rotational behavior (118.3 +/- 17.5 turns/h) following injection with apomorphine, a dopamine receptor agonist (0.5 mg/kg, sc). In contrast, acupunctural treatment at acupoints GB34 and LI3 was shown to significantly reduce this motor deficit (14.6 +/- 13.4 turns/h). Analysis via TH immunohistochemistry revealed a substantial loss of cell bodies in the substantia nigra (SN) (45.7% loss) and their terminals in the dorsolateral striatum ipsilateral to the 6-OHDA-induced lesion. However, acupunctural treatment resulted in the enhanced survival of dopaminergic neurons in the SN (21.4% loss) and their terminals in the dorsolateral striatum. Acupuncture also increased the expression of trkB significantly (35.6% increase) in the ipsilateral SN. In conclusion, we observed that only acupuncturing without the use of any drug has the neuroprotective effects against neuronal death in the rat PD model and these protective properties of acupuncture could be mediated by trkB.

Acupuncture Therapy↗

Pharmacological effects of SB 220025, a selective inhibitor of P38 mitogen-activated protein kinase, in angiogenesis and chronic inflammatory disease models.

Chronic inflammatory diseases often are accompanied by intense angiogenesis, supporting the destructive proliferation of inflammatory tissues. A model of inflammatory angiogenesis is the murine air pouch granuloma, which has a hyperangiogenic component. In this model, we explored the regulation of inflammatory angiogenesis using SB 220025, a specific inhibitor of human p38 mitogen-activated protein (MAP) kinase, with an IC50 value of 60 nM and 50- to 1000-fold selectivity vs. other kinases tested. In vivo, this compound reduced the lipopolysaccharide-induced production of tumor necrosis factor at an ED50 value of 7.5 mg/kg. In the inflammatory angiogenesis model, over the course of granuloma development, we observed elevated levels of interleukin-1beta and tumor necrosis factor-alpha during the chronic inflammatory phase when intense angiogenesis occurs. SB 220025 at 30 mg/kg b.i.d. p.o. was able to greatly reduce the expression of these cytokines and inhibit angiogenesis by approximately 40%. To further study the effects of p38/CSBP MAP kinase inhibition in angiogenesis-dependent chronic inflammatory disease, SB 220025 was tested in murine collagen-induced arthritis. In this model, SB 220025 was able to prevent the progression of established arthritis. Thus, this p38/CSBP MAP kinase inhibitor, which can reduce inflammatory cytokine production and inhibit angiogenesis, is an effective treatment for chronic proliferative inflammatory disease.

Animals↗

Early characterization of a novel metastatic disease model of murine neuroblastoma.

PURPOSE: We developed a measurable metastatic disease model of murine neuroblastoma. MATERIALS AND METHODS: Murine neuroblastoma cells (C1300) were cotransfected with plasmids encoding for neomycin resistance and beta-galactosidase. Transfected cells were selected by culture in media containing gentamicin. Monoclonal and polyclonal transfected cell lines were selected from surviving colonies. Three cell lines (M1, P1 and P2) were cultured and inoculated into female A/J mice. A control group was included for analysis. Animals were sacrificed on day 18 after injection, and primary tumors and organs were assayed for beta-galactosidase activity by chemoluminescence assay. Animal livers were stained with hematoxylin and eosin for histological assessment. RESULTS: Transfected primary tumor tissue demonstrated beta-galactosidase activity. Livers from control mice had no beta-galactosidase activity. Of the 3 cell lines tested M1 showed the highest levels of beta-galactosidase activity in liver and lung, suggesting homology with human disease. Kidneys from all experimental groups had elevated beta-galactosidase activity, suggesting that the kidney is a common metastatic site for murine neuroblastoma. Hematoxylin and eosin sections demonstrated normal livers in control mice and micrometastases in the livers of all experimental animals. CONCLUSIONS: A novel metastatic disease model for murine neuroblastoma has been developed. By transfecting tumor cells with genetic material encoding 2 marker proteins distant metastases may be detected by assay for beta-galactosidase or cells can be selected for neomycin resistance, even at a stage when they are difficult to identify by standard histological techniques.

Animals↗

An integration of three approaches to addiction and methadone maintenance treatment: the self-medication hypothesis, the disease model and social criticism.

The two models which have most affected theory and practice of addiction medicine have been the disease model and the self-medication hypothesis. The disease model's fundamental concept is that the addicted individual is sick and suffers from a disease. The self-medication hypothesis proposes that drug and alcohol users are attempting to cope with an underlying psychological or social disorder by means of self-medication. These two viewpoints are presented in the light of a number of specific methadone maintenance treatment and drug abuse related issues such as the question whether drug abuse is an illness of the body, the mind or society; whether the disease model really de-stigmatized drug abuse; what the correct methadone dosing policy should be; the place of psychotherapy in methadone maintenance treatment and drug abuse and how polydrug abuse should be treated. These issues are discussed and an integrated approach is suggested stressing the need for social criticism and a renewed social policy towards drug abuse in general and its treatment in particular.

Heroin Dependence↗