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Individuals with Autism Spectrum Disorder (ASD) experience a variety of symptoms that vary dramatically across individuals and can range from severe impairments to minor issues with social interactions and communication. The underlying cause of ASD is still unknown, and the level of influence that genetic and environmental factors have on the severity and occurrence of ASD is still a topic of great debate. Since the theories concerning cause or causes of ASD are multifactorial, the treatment options available are extremely limited and are based on behavioral testing. Alternatively, genetic testing might be considered in a diagnosis protocol. This study is designed to investigate ASD by assessing the variability of three genes associated with neuronal inhibition. Based on previous studies this experiment hypothesized that GAD1, GAD2, and PAVLB expression is decreased in Broca’s area in individuals with ASD when compared to controls, with the premise that this alteration could contribute to the symptoms involving language and communication. In situ hybridization was used to quantify the expression of the GAD1, GAD2, and PVALB genes in Broca’s area in postmortem human tissue. The variability of these three genes was quantified by measuring the amount of radioactively tagged mRNA in fifty cell bodies in each brain sample. This study used twenty-two brains of individuals with ASD and twenty-one control brains, including age matched males and females. The variables of age and sex are analyzed and discussed as well as the emulsion and film analyses. A decrease in parvalbumin expression was found between the ASD and control groups in Broca’s area. These finding were discussed in the context of symptoms and neuropathological features of ASD.

The pedunculopontine tegmental nucleus (PPN) and laterodorsal tegmental nucleus (LDT) are functionally associated brainstem structures implicated in behavioral state control and sensorimotor integration. The PPN is also involved in gait and posture, while the LDT plays a role in reward. Both nuclei comprise characteristic cholinergic neurons intermingled with glutamatergic and GABAergic cells whose absolute numbers in the rat have been only partly established. Here we sought to determine the complete phenotypical profile of each nucleus to investigate potential differences between them. Counts were obtained using stereological methods after the simultaneous visualization of cholinergic and either glutamatergic or GABAergic cells. The two isoforms of glutamic acid decarboxylase (GAD), GAD65 and GAD67, were separately analyzed. Dual in situ hybridization revealed coexpression of GAD65 and GAD67 mRNAs in ∼90% of GAD-positive cells in both nuclei; thus, the estimated mean numbers of (1) cholinergic, (2) glutamatergic, and (3) GABAergic cells in PPN and LDT, respectively, were (1) 3,360 and 3,650; (2) 5,910 and 5,190; and (3) 4,439 and 7,599. These data reveal significant differences between PPN and LDT in their relative phenotypical composition, which may underlie some of the functional differences observed between them. The estimation of glutamatergic cells was significantly higher in the caudal PPN, supporting the reported functional rostrocaudal segregation in this nucleus. Finally, a small subset of cholinergic neurons (8% in PPN and 5% in LDT) also expressed the glutamatergic marker Vglut2, providing anatomical evidence for a potential corelease of transmitters at specific target areas.

Type I Diabetes (T1D) is an autoimmune disease characterized by T cell-mediated inflammation of the pancreatic Islets of Langerhans, which results in beta (β) cell death and subsequent loss of insulin production. Ongoing human clinical trials suggest that targeting of autoreactive, β cell-specific T cells offers prospects for successful treatment of recent-onset T1D. The non-obese diabetic (NOD) mouse is an animal model of human T1D. T cell responses to glutamic acid decarboxylase 65kD (GAD65) are detectable in the spleens of prediabetic NOD mice and in the peripheral blood of prediabetic humans. T cells specific for GAD65 contribute to a diverse immune environment in the pancreas; responses to the immunogen can be either pathogenic or regulatory in nature. We have identified three carboxy terminal GAD65 determinants that yield either pathogenic cytotoxic T lymphocytes (CTL), T helper cells (Th1), or immunoregulatory T helper (Th2)-like T cell populations. GAD65 peptide 546-554 (p546)-specific CTL and GAD65 peptide 530-43 (p530)-specific Th1 are present in naïve NOD mice and are able to induce islet inflammation upon transfer into NOD severe combined immunodeficient (NOD.scid) recipients. GAD65 peptide 524-538 (p524)-specific Th2-like cells secrete IL-13 and suppress the activities of pathogenic Th1 cells. Since the three T cell-inducing epitopes are either proximal or overlapping in the GAD65 sequence, we wanted to investigate the processing mechanisms involved in epitope generation. We find that both macrophages and dendritic cells generate p546 from soluble, long GAD65 fragments by a TAP, ER, and proteasome-independent mechanism. While GAD65 p546 induces pathogenic CTL and GAD65 p530 induces proinflammatory Th1 cells, immunization with GAD65 p524-38 induces an immunoregulatory T cell population that protects NOD mice from T1D. p524-reactive T cells produce interleukin-13 (IL-13) that directly modulates IFN-γ production and proliferation of pathogenic GAD65 p530-5543 (p530)-specific T cells in NOD mice. Therefore, antigen processing and epitope selection may influence the balance dynamic between immune regulation and progressive autoimmune disease via the recruitment of specific T cell subsets.

Peripheral nerve injury is known to induce several changes in the physiology and morphology of the injured afferent. These changes include hyperexcitability, decreased dorsal root potentials (DRP), loss of synaptic vesicles as well as loss of the vesicular glutamate transporter, VGLUT1. While many of the changes caused by peripheral injury revert with regeneration, others appear to be permanent. The loss of the stretch reflex for example is a puzzling outcome of recovery after peripheral nerve transection and regeneration, especially given that the electrical counterpart of the stretch reflex (the H-reflex) recovers after regeneration. We hypothesized that stretch induced transmission is suppressed at the primary afferent – motor neuron synapse and sought to determine whether this was due to a decrease in excitatory transmission or an increase in presynaptic inhibition. To this end, we measured the level of expression of VGLUT1 and 2 as well as the GABA synthesizing enzyme GAD65 in the central terminals of physiologically characterized primary afferents from healthy Wistar rats for comparison with regenerated animals. An inverse relationship appears to exist between VGLUT1 and GAD65 expression. Expression of the two proteins also differ in laminae V, VII and IX, with the highest VGLUT1 immunoreactivity in lamina V and the highest number of GAD65-intense presynaptic boutons in lamina IX. The possible effects of regeneration on this pattern are discussed.