Additive Neuroprotective Effects of the Multifunctional Iron Chelator M30 with Enriched Diet in a Mouse Model of Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is the most common degenerative disease of the motoneuron system, involving various abnormalities, such as mitochondrial dysfunction, oxidative stress, transitional metal accumulation, neuroinflammation, glutamate excitotoxicity, apoptosis, decreased supply of trophic factors, cytoskeletal abnormalities, and extracellular superoxide dismutase (SOD)-1 toxicity. These multiple disease etiologies implicated in ALS gave rise to the perception that future therapeutic approaches for the disease should be aimed at targeting multiple pathological pathways. In line with this view, we have evaluated in the current study the therapeutic effects of low doses of the novel multifunctional monoamine oxidase (MAO) inhibitor/iron-chelating compound, M30 in combination with high Calorie Energy supplemented Diet (CED) in the SOD1-G93A transgenic mouse model of ALS. Our results demonstrated that the combined administration of M30 with CED produced additive neuroprotective effects on motor performance and increased survival of SOD1-G93A mice. We also found that both M30 and M30/CED regimens caused a significant inhibition of MAO-A and -B activities and decreased the turnover of dopamine in the brain of SOD1-G93A mice. In addition, M30/CED combined treatment resulted in a significant increase in mRNA expression levels of various mitochondrial biogenesis and metabolism regulators, such as peroxisome proliferator-activated receptor-γ (PPARγ)-co activator 1 alpha (PGC-1α), PPARγ, uncoupling protein 1, and insulin receptor in the gastrocnemius muscle of SOD1-G93A mice. These results suggest that a combination of drug/agents with different, but complementary mechanisms may be beneficial in the treatment of ALS.

The novel multi-target iron chelator, M30 modulates HIF-1α-related glycolytic genes and insulin signaling pathway in the frontal cortex of APP/PS1 Alzheimer's disease mice.

Increasing evidence suggests that dysregulation of brain insulin/insulin receptor (InsR) and insulin signaling cascade are associated with the pathogenesis of Alzheimer's disease (AD). Our group has designed and synthesized a series of multi-target iron chelating, brain permeable compounds for AD. One leading multi-target compound, M30 possesses the neuroprotective N-propargyl moiety of the anti-Parkinsonian, monoamine oxidase (MAO)-B inhibitor, rasagiline (Azilect®) and the antioxidant-iron chelating moiety of an 8-hydroxyquinoline derivative of the iron chelator, VK28. Positive outcomes for the behavioral/cognitive and neuroprotective effects of M30 were recently obtained in preclinical experimental studies, regarding pathological aspects relevant to ageing and AD. We report that chronic treatment with M30 (1 and 5 mg/kg p.o; three times a week for 9 months) significantly elevated cortical insulin and InsR transcript and protein expression, respectively and increased the phosphorylated form of glycogen synthase kinase-3ß in the frontal cortex of amyloid precursor protein (APP) and presenilin 1 (PS1) double transgenic mice. In addition, M30 treatment upregulated the levels of hypoxia-inducible factor (HIF)-1α and expression of its target genes involved in glycolysis including, aldolase A, enolase-1 and glucose transporter-1 (Glut-1), in the frontal cortex of APP/PS1 mice. Treatment with M30 also lead to an increase in the hepatic protein expression levels of InsR and Glut-1 and lowered the increase in blood glucose levels following glucose tolerance test. The present findings indicate that the multifunctional iron chelating drug, M30 regulates major brain glucose metabolism parameters and thus, might be beneficial for AD, in which impaired neuronal insulin signaling and Glut expression have been implicated.

Novel multifunctional neuroprotective iron chelator-monoamine oxidase inhibitor drugs for neurodegenerative diseases. In vivo selective brain monoamine oxidase inhibition and prevention of MPTP-induced striatal dopamine depletion.

Several multifunctional iron chelators have been synthesized from hydroxyquinoline pharmacophore of the iron chelator, VK-28, possessing the monoamine oxidase (MAO) and neuroprotective N-propargylamine moiety. They have iron chelating potency similar to desferal. M30 is a potent irreversible rat brain mitochondrial MAO-A and -B inhibitor in vitro (IC50, MAO-A, 0.037 +/- 0.02; MAO-B, 0.057 +/- 0.01). Acute (1-5 mg/kg) and chronic [5-10 mg/kg intraperitoneally (i.p.) or orally (p.o.) once daily for 14 days]in vivo studies have shown M30 to be a potent brain selective (striatum, hippocampus and cerebellum) MAO-A and -B inhibitor. It has little effects on the enzyme activities of the liver and small intestine. Its N-desmethylated derivative, M30A is significantly less active. Acute and chronic treatment with M30 results in increased levels of dopamine (DA), serotonin(5-HT), noradrenaline (NA) and decreases in DOPAC (dihydroxyphenylacetic acid), HVA (homovanillic acid) and 5-HIAA (5-hydroxyindole acetic acid) as determined in striatum and hypothalamus. In the mouse MPTP (N-methy-4-phenyl-1,2,3,6-tetrahydropyridine) model of Parkinson's disease (PD) it attenuates the DA depleting action of the neurotoxin and increases striatal levels of DA, 5-HT and NA, while decreasing their metabolites. As DA is equally well metabolized by MAO-A and -B, it is expected that M30 would have a greater DA neurotransmission potentiation in PD than selective MAO-B inhibitors, for which it is being developed, as MAO-B inhibitors do not alter brain dopamine.

Amelioration of diabetes in nonobese diabetic mice with advanced disease by linomide-induced immunoregulation combined with Reg protein treatment.

Oral linomide, (quinoline-3-carboxamide), has been shown to prevent autoimmune insulitis, islet destruction, and diabetes in NOD mice treated at an early stage of the disease, but confers only partial protection in animals with advanced disease. Reg protein, the gene product of a complementary DNA isolated from a regenerating rat islet library, has been previously shown to induce expansion of beta-cell mass in pancreatectomized rats. To determine the effect of treatment combining immunomodulation and Reg protein on advanced autoimmune diabetes, we treated female NOD mice with oral linomide and i.p. Reg protein injections. In 14-week-old animals with less severe disease (glucose tolerant), treatment with each agent alone resulted in amelioration of diabetes, as did treatment with Reg alone in 5-week-old prediabetic mice. In 14-week-old animals with more severe disease (glucose intolerant), only treatment with the combination of both agents, but not that with each separately, resulted in amelioration of diabetes. Our study suggests that treatment aimed at abrogation of autoimmunity combined with expansion of beta-cell mass constitutes a potential therapeutic approach for treatment of insulin-dependent diabetes mellitus.

[Effect of different concentrations of various zinc complexes (picolinate, citrate, 8-hydroxyquinolate) in comparison with sulfate on zinc supply status in rats]. / Der Einfluss unterschiedlicher Konzentrationen an verschiedenen Zinkkomplexen (Picolinat, Citrat, 8-Hydroxychinolat) im Vergleich zu Sulfat auf Parameter des Zn-Versorgungsstatus von Ratten.

12 groups of 8 young male Sprague-Dawley rats received a semisynthetic casein-diet, whose zinc concentration (1.3 ppm) was adjusted to 5, 10 and 15 ppm by supplementation of various Zn complexes or salts like Zn citrate, Zn picolinate, Zn 8-hydroxyquinolate and Zn sulfate. After 24 days all animals were killed and examined on parameters of zinc supply status. The weight gain of the animals with 5 ppm dietary zinc was strongly reduced compared to groups with the higher dietary zinc content. The type of the supplemented Zn compound showed in no way an influence on the live-weight of the animals. The zinc concentration of the tissues, too, was only dependent on the level of the dietary zinc concentration and not on the type of supplemented zinc compound. The activity of the alkaline phosphatase in serum, a zinc metalloenzyme, was altogether reduced in the zinc-deficient animals with 5 ppm dietary zinc content, but showed a significant higher activity in the citrate and 8-hydroxyquinolate group than in the sulfate and picolinate group. Also the percent zinc-binding capacity of serum, a good indicator for estimating the zinc supply status of rats, showed a better zinc supply of the citrate group with 5 as well as 10 ppm dietary zinc, compared with the other groups on the same dietary zinc content. The serum zinc concentration of rats with 5 ppm as Zn citrate was more than twice higher than in animals given zinc as picolinate, 8-hydroxyquinolate or sulfate. The results indicate a better utilization of zinc chelated by citric acid than by picolinic acid, 8-hydroxyquinoline or as salt like sulfate. But the higher bioavailability of zinc in human milk should not only be attributed to the presence of citrate.