N-butyldeoxynojirimycin causes weight loss as a result of appetite suppression in lean and obese mice

N-Acetyl-L-leucine improves functional recovery and attenuates cortical cell death and neuroinflammation after traumatic brain injury in mice

Traumatic brain injury (TBI) is a major cause of mortality and long-term disability around the world. Even mild to moderate TBI can lead to lifelong neurological impairment due to acute and progressive neurodegeneration and neuroinflammation induced by the injury. Thus, the discovery of novel treatments which can be used as early therapeutic interventions following TBI is essential to restrict neuronal cell death and neuroinflammation. We demonstrate that orally administered N-acetyl-l-leucine (NALL) significantly improved motor and cognitive outcomes in the injured mice, led to the attenuation of cell death, and reduced the expression of neuroinflammatory markers after controlled cortical impact (CCI) induced experimental TBI in mice. Our data indicate that partial restoration of autophagy flux mediated by NALL may account for the positive effect of treatment in the injured mouse brain. Taken together, our study indicates that treatment with NALL would be expected to improve neurological function after injury by restricting cortical cell death and neuroinflammation. Therefore, NALL is a promising novel, neuroprotective drug candidate for the treatment of TBI.

Acetyl-leucine slows disease progression in lysosomal storage disorders

Acetyl-dl-leucine is a derivative of the branched chain amino acid leucine. In observational clinical studies, acetyl-dl-leucine improved symptoms of ataxia, in particular in patients with the lysosomal storage disorder, Niemann-Pick disease type C1. Here, we investigated acetyl-dl-leucine and its enantiomers acetyl-l-leucine and acetyl-d-leucine in symptomatic Npc1^-/- mice and observed improvement in ataxia with both individual enantiomers and acetyl-dl-leucine. When acetyl-dl-leucine and acetyl-l-leucine were administered pre-symptomatically to Npc1^-/- mice, both treatments delayed disease progression and extended life span, whereas acetyl-d-leucine did not. These data are consistent with acetyl-l-leucine being the neuroprotective enantiomer. Altered glucose and antioxidant metabolism were implicated as one of the potential mechanisms of action of the l-enantiomer in Npc1^-/- mice. When the standard of care drug miglustat and acetyl-dl-leucine were used in combination significant synergy resulted. In agreement with these pre-clinical data, when Niemann-Pick disease type C1 patients were evaluated after 12 months of acetyl-dl-leucine treatment, rates of disease progression were slowed, with stabilization or improvement in multiple neurological domains. A beneficial effect of acetyl-dl-leucine on gait was also observed in this study in a mouse model of GM2 gangliosidosis (Sandhoff disease) and in Tay-Sachs and Sandhoff disease patients in individual-cases of off-label-use. Taken together, we have identified an unanticipated neuroprotective effect of acetyl-l-leucine and underlying mechanisms of action in lysosomal storage diseases, supporting its further evaluation in clinical trials in lysosomal disorders.

Subacute Oral Administration of Clinacanthus nutans Ethanolic Leaf Extract Induced Liver and Kidney Toxicities in ICR Mice

This study investigated the leaves of Clinacanthus nutans for its bioactive compounds and acute and subacute toxicity effects of C. nutans ethanolic leaf extract (CELE) on blood, liver and kidneys of ICR mice. A total of 10 8-week-old female mice were divided into groups A (control) and B (2000 mg/kg) for the acute toxicity study. A single dose of 2000 mg/kg was administered to group B through oral gavage and mice were monitored for 14 days. In the subacute toxicity study, mice were divided into five groups: A (control), B (125 mg/kg), C (250 mg/kg), D (500 mg/kg) and E (1000 mg/kg). The extract was administered daily for 28 days via oral gavage. The mice were sacrificed, and samples were collected for analyses. Myricetin, orientin, isoorientin, vitexin, isovitexin, isookanin, apigenin and ferulic acid were identified in the extract. Twenty-eight days of continuous oral administration revealed significant increases (p < 0.05) in creatinine, ALT and moderate hepatic and renal necrosis in groups D and E. The study concluded that the lethal dose (LD₅₀) of CELE in mice is greater than 2000 mg/kg and that repeated oral administrations of CELE for 28 days induced hepatic and renal toxicities at 1000 mg/kg in female ICR mice.

N-Ethyl-n-Nitrosourea Induced Leukaemia in a Mouse Model through Upregulation of Vascular Endothelial Growth Factor and Evading Apoptosis

Chemical carcinogens are commonly used to investigate the biology and prognoses of various cancers. This study investigated the mechanism of leukaemogenic effects of n-ethyl-n-nitrosourea (ENU) in a mouse model. A total of 14 3-week-old male Institute of Cancer Research (ICR)-mice were used for the study. The mice were divided into groups A and B with seven mice each. Group A served as the control while group B received intraperitoneal (IP) injections of 80 mg/kg ENU twice with a one-week interval and were monitored monthly for 3 months for the development of leukaemia via blood smear examination. The mice were sacrificed humanely using a CO₂ chamber. Blood, spleen, lymph nodes, liver, kidney and lung samples were collected for blood smear examination and histopathological evaluation. The expression of angiogenic protein (VEGF), and pro and anti-apoptotic proteins (BCL2 and BAX), was detected and quantified using Western blot technique. Leukaemia was confirmed by the presence of numerous blast cells in the peripheral blood smear in group B. Similarly, the VEGF and BCL2 proteins were significantly (p < 0.05) upregulated in group B compared to A. It is concluded that IP administration of 80 mg/kg ENU induced leukaemia in ICR-mice 12 weeks post administration through upregulation of angiogenic and anti-apoptotic proteins: VEGF and BCL2.

AAV9 intracerebroventricular gene therapy improves lifespan, locomotor function and pathology in a mouse model of Niemann-Pick type C1 disease

Niemann-Pick type C disease (NP-C) is a fatal neurodegenerative lysosomal storage disorder. It is caused in 95% of cases by a mutation in the NPC1 gene that encodes NPC1, an integral transmembrane protein localized to the limiting membrane of the lysosome. There is no cure for NP-C but there is a disease-modifying drug (miglustat) that slows disease progression but with associated side effects. Here, we demonstrate in a well-characterized mouse model of NP-C that a single administration of AAV-mediated gene therapy to the brain can significantly extend lifespan, improve quality of life, prevent or ameliorate neurodegeneration, reduce biochemical pathology and normalize or improve various indices of motor function. Over-expression of human NPC1 does not cause adverse effects in the brain and correctly localizes to late endosomal/lysosomal compartments. Furthermore, we directly compare gene therapy to licensed miglustat. Even at a low dose, gene therapy has all the benefits of miglustat but without adverse effects. On the basis of these findings and on-going ascendency of the field, we propose intracerebroventricular gene therapy as a potential therapeutic option for clinical use in NP-C.

Design of a New α-1-C-Alkyl-DAB Derivative Acting as a Pharmacological Chaperone for β-Glucocerebrosidase Using Ligand Docking and Molecular Dynamics Simulation

Some point mutations in β-glucocerebrosidase cause either improper folding or instability of this protein, resulting in Gaucher disease. Pharmacological chaperones bind to the mutant enzyme and stabilize this enzyme; thus, pharmacological chaperone therapy was proposed as a potential treatment for Gaucher disease. The binding affinities of α-1-C-alkyl 1,4-dideoxy-1,4-imino-d-arabinitol (DAB) derivatives, which act as pharmacological chaperones for β-glucocerebrosidase, abruptly increased upon elongation of their alkyl chain. In this study, the primary causes of such an increase in binding affinity were analyzed using protein–ligand docking and molecular dynamics simulations. We found that the activity cliff between α-1-C-heptyl-DAB and α-1-C-octyl-DAB was due to the shape and size of the hydrophobic binding site accommodating the alkyl chains, and that the interaction with this hydrophobic site controlled the binding affinity of the ligands well. Furthermore, based on the aromatic/hydrophobic properties of the binding site, a 7-(tetralin-2-yl)-heptyl-DAB compound was designed and synthesized. This compound had significantly enhanced activity. The design strategy in consideration of aromatic interactions in the hydrophobic pocket was useful for generating effective pharmacological chaperones for the treatment of Gaucher disease.

Central Administration of 1-Deoxynojirimycin Attenuates Hypothalamic Endoplasmic Reticulum Stress and Regulates Food Intake and Body Weight in Mice with High-Fat Diet-Induced Obesity

The α-glucosidase inhibitor, 1-deoxynojirimycin (DNJ), is widely used for its antiobesity and antidiabetic effects. Researchers have demonstrated that DNJ regulates body weight by increasing adiponectin levels, which affects energy intake and prevents diet-induced obesity. However, the mechanism by which centrally administered DNJ exerts anorexigenic effects has not been studied until now. We investigated the effect of DNJ in the hypothalamus of mice with high-fat diet-induced obesity. Results showed that intracerebroventricular (ICV) administration of DNJ reduced hypothalamic ER stress, which activated the leptin-induced Janus-activated kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) signaling pathway to cause appetite suppression. We conclude that DNJ may reduce obesity by moderating feeding behavior and ER stress in the hypothalamic portion of the central nervous system (CNS).

Terminal arteriolar network structure/function and plasma cytokine levels in db/db and ob/ob mouse skeletal muscle

OBJECTIVE

To investigate the terminal arteriolar network structure and function in relation to circulating plasma cytokine levels in db/db, ob/ob, and their genetic background control, C57/bl6, mice.

METHODS

Arteriolar network size and erythrocyte distribution were observed in the resting cremaster muscle (n = 45, pentobarbital 50 mg/kg i.p.). Structural remodeling and inflammatory state were related to 21 plasma cytokine levels.

RESULTS

db/db networks were shorter, had fewer branches, and smaller diameters than C57/bl6 controls. ob/ob networks were longer, with similar branch numbers, however with non-uniform diameters. Shunting of erythrocytes to the specific terminal arteriolar branches of the network (functional rarefaction) was prominent in db/db and ob/ob, with further evidence of shunting between networks seen as no flow to 50% of ob/ob arteriolar networks.

CONCLUSIONS

Altered levels of plasma cytokines are consistent with structural remodeling seen in db/db, and a pro-inflammatory state for both db/db and ob/ob. Differences in network structure alone predict overall reduced uniform oxygen delivery in db/db or ob/ob. Shunting probably increases heterogeneous oxygen delivery and is strain-dependent.