title: Flupirtine blocks apoptosis in batten patient lymphoblasts and in human postmitotic CLN3- and CLN2-deficient neurons.
abstract: Multiple gene defects cause Batten disease. Accelerated apoptosis accounts for neurodegeneration in the late infantile and juvenile forms that are due to defects in the CLN3 and CLN2 genes. Extensive neuronal death is seen in CLN2- and CLN3-deficient human brain as well as in CLN6-deficient sheep brain and retina. When neurons in late infantile and juvenile brain survive, they manage to do so by upregulating the neuroprotective molecule Bcl-2. The CLN3 gene has antiapoptotic properties at the molecular level. We show that the CLN2 gene is neuroprotective: it enhances growth of NT2 cells and maintains survival of human postmitotic hNT neurons. Conversely, blocking CLN3 or CLN2 expression in hNT neurons with adenoviral antisense-CLN3 or antisense-CLN2-AAV2 constructs causes apoptosis. The drug flupirtine is a triaminopyridine derivative that acts as a nonopioid analgesic. Flupirtine upregulates Bcl-2, increases glutathione levels, activates an inwardly rectifying potassium channel, and delays loss of intermitochondrial membrane calcium retention capacity. We show that flupirtine aborts etoposide-induced apoptosis in CLN1-, CLN2-, CLN3-, and CLN6-deficient as well as normal lymphoblasts. Flupirtine also prevents the death of CLN3- and CLN2-deficient postmitotic hNT neurons at the mitochondrial level. We show that a mechanism of neuroprotection exerted by flupirtine involves complete functional antagonism of N-methyl-D-aspartate or N-methyl-D-aspartate-induced neuronal apoptosis. Flupirtine may be useful as a drug capable of halting the progression of neurodegenerative diseases caused by dysregulated apoptosis.
authors.affiliation: Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Sumeer
authors.initials: S
authors.lastname: Dhar
authors.forename: Rhonda L
authors.initials: RL
authors.lastname: Bitting
authors.forename: Svetlana N
authors.initials: SN
authors.lastname: Rylova
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Jansen
authors.forename: Ellen
authors.initials: E
authors.lastname: Lockhart
authors.forename: Dwight D
authors.initials: DD
authors.lastname: Koeberl
authors.forename: Andrea
authors.initials: A
authors.lastname: Amalfitano
authors.forename: Rose-Mary N
authors.initials: RM
authors.lastname: Boustany
mesh_terms: D000626:Aminopeptidases; D000631:Aminopyridines / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D010450:Endopeptidases; D015870:Gene Expression; D006801:Humans; D020287:In Situ Nick-End Labeling; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000235:genetics; D008938:Mitosis; D018832:Molecular Chaperones; D009472:Neuronal Ceroid-Lipofuscinoses / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010447:Peptide Hydrolases / Q000235:genetics*; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D057057:Serine Proteases; D018243:Teratocarcinoma; D013869:Thiolester Hydrolases; D014162:Transfection; D000091346:Tripeptidyl-Peptidase 1; D014407:Tumor Cells, Cultured
chemical_list: D000631:Aminopyridines; C105199:CLN3 protein, human; C447500:CLN6 protein, human; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D018832:Molecular Chaperones; D018696:Neuroprotective Agents; D011506:Proteins; D012333:RNA, Messenger; D000091346:Tripeptidyl-Peptidase 1; D013869:Thiolester Hydrolases; C416054:PPT1 protein, human; D010450:Endopeptidases; D010447:Peptide Hydrolases; D057057:Serine Proteases; D000626:Aminopeptidases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C000717267:TPP1 protein, human; C034161:flupirtine