IgG entry and deposition are components of the neuroimmune response in Batten disease.

Patients and a mouse model of Batten disease, the juvenile form of neuronal ceroid lipofuscinosis (JNCL), raise autoantibodies against GAD65 and other brain-directed antigens. Here we investigate the adaptive component of the neuroimmune response. Cln3(-/-) mice have autoantibodies to GAD65 in their cerebrospinal fluid and elevated levels of brain bound immunoglobulin G (IgG). IgG deposition was found within human JNCL autopsy material, a feature that became more evident with increased age in Cln3(-/-) mice. The lymphocyte infiltration present in human and murine JNCL occurred late in disease progression, and was not capable of central/intrathecal IgG production. In contrast, we found evidence for an early systemic immune dysregulation in Cln3(-/-) mice. In addition evidence for a size-selective breach in the blood-brain barrier integrity in these mice suggests that systemically produced autoantibodies can access the JNCL central nervous system and contribute to a progressive inflammatory response.

Glial activation spreads from specific cerebral foci and precedes neurodegeneration in presymptomatic ovine neuronal ceroid lipofuscinosis (CLN6).

The neuronal ceroid lipofuscinoses (NCLs, Batten disease) are fatal inherited neurodegenerative diseases characterized by gross brain atrophy, blindness, and intracellular accumulation of lysosome-derived storage bodies. A CLN6 form in sheep is studied as a large animal model of the human diseases. This study describes neuropathological changes in brains from presymptomatic affected sheep. Activated astrocytes and focal clusters of activated microglia were present in outer layers of occipital and somatosensory cortical regions as early as 12 days of age, together with activated perivascular macrophages. Astrocytic activation and progressive transformation of microglia to brain macrophages preceded neurodegeneration and spread to different cortical areas, most prominently in regions associated with clinical symptoms. In contrast, storage body accumulation was much more evenly spread across regions. These data support suggestions that neurodegeneration and storage body accumulation may be independent manifestations of CLN6 mutation and indicate that glial cell activation may be an important mediator in pathogenesis.

A novel somatodendritic marker defined by a peptide derived from the ALS2 protein.

We characterized an antibody raised against a peptide derived from the ALS2 protein, the product of a gene linked to recessive juvenile forms of amyotrophic lateral sclerosis, defining the ALS2 RLD-derived antigen (ARDA). In cultured rat cortical neurons, ARDA is localized in perikarya and neurites, but absent from nuclei. Double immunostaining of rodent cultured neurons and spinal cord sections for ARDA and MAP2, a marker of dendrites, or tau and phosphorylated neurofilaments, markers of axons, demonstrated that the ARDA antigen was localized in the somatodendritic compartment and excluded from axons. ARDA was also selectively localized to the somatodendritic compartment of motor neurons in human spinal cord. The ARDA antigen therefore represents a novel somatodendritic marker for embryonic and adult neurons.

The neuronal adaptor protein X11alpha reduces Abeta levels in the brains of Alzheimer's APPswe Tg2576 transgenic mice.

Increased production and deposition of the 40-42-amino acid beta-amyloid peptide (Abeta) is believed to be central to the pathogenesis of Alzheimer's disease. Abeta is derived from the amyloid precursor protein (APP), but the mechanisms that regulate APP processing to produce Abeta are not fully understood. X11alpha (also known as munc-18-interacting protein-1 (Mint1)) is a neuronal adaptor protein that binds APP and modulates APP processing in transfected non-neuronal cells. To investigate the in vivo effect of X11alpha on Abeta production in the brain, we created transgenic mice that overexpress X11alpha and crossed these with transgenics harboring a familial Alzheimer's disease mutant APP that produces increased levels of Abeta (APPswe Tg2576 mice). Analyses of Abeta levels in the offspring generated from two separate X11alpha founder mice revealed a significant, approximate 20% decrease in Abeta(1-40) in double transgenic mice expressing APPswe/X11alpha compared with APPswe mice. At a key time point in Abeta plaque deposition (8 months old), the number of Abeta plaques was also deceased in APPswe/X11alpha mice. Thus, we report here the first demonstration that X11alpha inhibits Abeta production and deposition in vivo in the brain.

Identification of a novel, membrane-associated neuronal kinase, cyclin-dependent kinase 5/p35-regulated kinase.

Here we characterize a novel neuronal kinase, cyclin-dependent kinase 5 (cdk5)/p35-regulated kinase (cprk). Cprk is a member of a previously undescribed family of kinases that are predicted to contain two N-terminal membrane-spanning domains and a long C terminus, which harbors a dual-specificity serine/threonine/tyrosine kinase domain. Cprk was isolated in a yeast two-hybrid screen using the neuronal cdk5 activator p35 as "bait." Cprk interacts with p35 in the yeast-two hybrid system, binds to p35 in glutathione S-transferase fusion pull-down assays, and colocalizes with p35 in cultured neurons and transfected cells. In these cells, cprk is present with p35 in the Golgi apparatus. Cprk is expressed in a number of tissues but is enriched in brain and muscle and within the brain is found in a wide range of neuronal populations. Cprk displays catalytic activity in in vitro kinase assays and is itself phosphorylated by cdk5/p35. Cdk5/p35 inhibits cprk activity. Cdk5/p35 may therefore regulate cprk function in the brain.