Goals

Alzheimer’s disease is the most common cause of dementia in the elderly and remains a devastating disease with currently no cure or effective therapies.  The exact pathogenesis of Alzheimer’s disease is still unclear, but a leading hypothesis is that the abnormal accumulation of amyloid-beta peptides leads to the dementia.  While deficits in cognition and memory are the major clinical manifestations of Alzheimer’s disease, accelerated early body weight loss often occurs prior to the mental decline.  Furthermore, weight loss is correlated with worsening disease progression and increased risk of death in Alzheimer’s disease.  Therefore, brain circuits regulating body weight may be altered early in Alzheimer’s disease and could be intrinsic to the disease process.  Our laboratory is interested in identifying the central and peripheral pathways regulating body weight and systemic metabolism that are altered early in Alzheimer’s disease. 

We approach this topic by:

  • Investigating how amyloid-beta disrupts brain circuits in the hypothalamus, a brain region that critically regulates body weight, and how this differs from normal aging-related weight loss

  • Examining how disruption of specific hypothalamic neurons by amyloid-beta and other associated factors lead to systemic metabolic deficits

  • Identifying alterations in key metabolic factors and signaling pathways in human study volunteers at the earliest stages of Alzheimer’s disease

To address these aims, we have adopted a “bench-to-bedside” strategy and utilize genetic, molecular, and neurophysiological approaches in mouse models, and validation in clinically relevant human studies.

 
 
Figure 2: Deficits in body weight and plasma leptin levels worsen with increasing age and brain amyloid-beta brain burden in a transgenic mouse model overexpressing the amyloid precursor protein (Adapted from Ishii et al., J Neuroscience 2014)

Figure 2: Deficits in body weight and plasma leptin levels worsen with increasing age and brain amyloid-beta brain burden in a transgenic mouse model overexpressing the amyloid precursor protein (Adapted from Ishii et al., J Neuroscience 2014)

Figure 3: 3 month-old transgenic mice over-expressing amyloid precursor protein (Tg2576) have significantly lower body adiposity (white hyper-intense signals on T1-weighted MRI) compared to wild-type (WT) littermates. (Adapted from Ishii et al., J Neuroscience 2014)

 
Figure 4: GFP labeled NPY neurons in the arcuate nuclei of the hypothalamus are evaluated by whole-cell patch clamp (with collaborator Dr. Gang Wang, BMRI).

Figure 4: GFP labeled NPY neurons in the arcuate nuclei of the hypothalamus are evaluated by whole-cell patch clamp (with collaborator Dr. Gang Wang, BMRI).

 
Figure 5: Schematic of a proposed pathophysiological mechanism for amyloid-beta mediated inhibition of hypothalamic pathways leading to weight loss and a low leptin state. (Adapted from Ishii et al., J Neuroscience 2014)

Figure 5: Schematic of a proposed pathophysiological mechanism for amyloid-beta mediated inhibition of hypothalamic pathways leading to weight loss and a low leptin state. (Adapted from Ishii et al., J Neuroscience 2014)

 

Long Term Goals

By elucidating the molecular mechanisms underlying alterations in body weight/systemic metabolism in Alzheimer’s disease, we hope to advance our overall understanding of the complex interaction between body weight/systemic metabolism and brain function. The ultimate long-term goal of the laboratory is to translate these findings to the development of new diagnostic tools and novel therapeutic agents.

Achievements

Publications

research - basic/translational

  1. Ishii, M., Hiller, A. J., Pham, L., Mcguire, M. J., Iadecola, C., & Wang, G. (2019). Amyloid-Beta Modulates Low-Threshold Activated Voltage-Gated L-Type Calcium Channels of Arcuate Neuropeptide Y Neurons Leading to Calcium Dysregulation and Hypothalamic Dysfunction. The Journal of Neuroscience, 39(44), 8816-8825.

  2. Ishii, M., Wang, G., Racchumi, G., Dyke, J. P. Iadecola, C. (2014). Transgenic mice overexpressing amyloid precursor protein exhibit early metabolic deficits and a pathologically low leptin state associated with hypothalamic dysfunction in arcuate neuropeptide Y neurons. J. Neuroscience, 34 (27): 9096-9106.

  3. Nagata-Kuroiwa, R., Furutani, N., Hara, J., Hondo, M., Ishii, M., Abe, T., Mieda, M., Tsujino, N., Motoike, T., Yanagawa, Y., Kuwaki, T., Yamamoto, M., Yanagisawa, M., Sakurai, T. (2011). Critical role of neuropeptides b/w receptor 1 signaling in social behavior and fear memory. PLoS One. Feb 24; 6 (2): e16972.  

  4. Sakakibara, I., Fujino, T., Ishii, M., Tanaka, T., Shimosawa, T., Miura, S., Zhang, W., Tokutake, Y., Yamamoto, J., Awano, M., Iwasaki, S., Motoike, T, Okamura, M., Inagaki T., Kita K., Ezaki, O., Naito, M., Kuwaki, T., Chohnan, S., Yamamoto, TT., Hammer, RE., Kodama, T., Yanagisawa, M., Sakai, J. (2009). Fasting-induced hypothermia and reduced energy production in mice lacking acetyl-CoA synthetase 2. Cell Metabolism, 9 (2):191-202.

  5. Aikawa, S., Ishii, M., Yanagisawa M., Sakakibara Y., and Sakurai, T. (2008).  Effect of neuropeptide B on feeding behavior is influenced by endogenous corticotrophin-releasing factor activities. Regulatory Peptides, 151 (1-3): 147-152.

  6. Kitamura, Y., Tanaka, H., Motoike, T., Williams, S. C., Ishii, M., Yanagisawa, M., and Sakurai, T (2006). Distribution of Neuropeptide W immunoreactivity and mRNA in Adult Rat Brain. Brain Research, 1093(1):123-34.

  7. Ishii, M., Fei, H., and Friedman, J. M (2003). Targeted disruption of GPR7, the endogenous receptor for neuropeptides B and W, leads to metabolic defects and adult-onset obesity. Proc. Natl. Acad. Sci. USA, 100: 10540-10545.

  8. Khalil, E. M., De Angelis J., Ishii, M., Cole, P. A. (1999). Mechanism-based inhibition of the melatonin rhythm enzyme: Pharmacologic exploitation of active site functional plasticity.  Proc. Natl. Acad. Sci. USA, 96, 22, 12418-12423.

  9. Sakurai, T., Amemiya, A., Ishii, M., Matsuzaki, I., Chimelli, R.M., Tanaka, H., Williams, S.C., Richardson, J.A., Kozlowski, G.P., Wilson, S., Arch, J.R.S., Buckingham, R.E., Haynes, A.C., Carr, S.A., Annan, R.S., McNutty, D.E., Liu, W., Terrett, J.A., Eishourbagy, N.A., Bergsma, D.J., and Yanagisawa, M. (1998). Orexins and Orexin Receptors: A Family of Hypothalamic Neuropeptides and G Protein-Coupled Receptors that Regulate Feeding Behavior. Cell, 92, 573-585.

Research - clinical

  1. Eruysal, E., Ravdin, L., Kamel, H., Iadecola, C., & Ishii, M. (2019). Plasma lipocalin‐2 levels in the preclinical stage of Alzheimer's disease. Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring, 11(1), 646-653.

  2. Ishii, M., Kamel, H., & Iadecola, C. (2019). Retinol Binding Protein 4 Levels Are Not Altered in Preclinical Alzheimer’s Disease and Not Associated with Cognitive Decline or Incident Dementia. Journal of Alzheimer's Disease, 67(1), 257-263.

  3. Weaver, J., Sarva H., Barone, D., Bobker, S., Bushara, K., Hiller, A., Ishii, M., Jankovic, J., Lakhani, S., Niotis, K., Scharre, D. W., Tuite, P., Stutz, A., Westhoff, CM., Walker, R. H. (2019). McLeod syndrome: Five new pedigrees with novel mutations. Parkinsonism and Related Disorders, 64: 293-299.

  4. Ishii, M., Lavi, E., Kamel, H., Gupta, A., Iadecola, C., Navi, B. B. (2014). Amyloid Beta-related Central Nervous System Angiitis Presenting with an Isolated Seizure. Neurohospitalist, 4 (2):86-89.

invited commentaries and Reviews (PEer-reviewed)

  1. Ishii, M., Iadecola C. (2020). A novel neurovascular liaison governing the blood-brain barrier. Neuron, 107 (2): 205-207

  2. Ishii M., Iadecola C. (2020). Risk factor for Alzheimer's disease breaks the blood-brain barrier. Nature, 581(7806): 31-32.

  3. Ishii, M. (2019). Apolipoprotein B as a New Link Between Cholesterol and Alzheimer Disease. JAMA Neurology, 76(7), 751.

  4. Hiller, A. and Ishii, M. (2018). Disorders of Body Weight, Sleep and Circadian Rhythm as Manifestations of Hypothalamic Dysfunction in Alzheimer’s Disease. Frontiers in Cellular Neuroscience, 12:471. doi: 10.3389/fncel.2018.00471

  5. Ishii, M. (2017). Endocrine Emergencies With Neurologic Manifestations. CONTINUUM: Lifelong Learning in Neurology, 23(3), 778-801.

  6. McGuire, M. J., and Ishii, M. (2016). Leptin dysfunction and Alzheimer’s disease: evidence from cellular, animal, and human studies. Cellular and Molecular Neurobiology, 36 (2): 203-217.

  7. Ishii, M. and Iadecola, C. (2016). Adipocyte-derived factors in age-related dementia and their contribution to vascular and Alzheimer pathology. Biochimica et Biophysica Acta Molecular Basis of Disease, 1862 (5): 966-974.

  8. Ishii, M.* and Iadecola, C. (2015).  Metabolic and non-cognitive manifestations of Alzheimer’s disease: the hypothalamus as both culprit and target. Cell Metabolism, 22 (5): 761-776. *corresponding author

  9. Ishii, M. (2014). Neurologic Complications of Non-Diabetic Endocrine Disorders. Continuum: Lifelong Learning in Neurology, 20 (3): 560-579

  10. Hondo, M., Ishii, M., and Sakurai, T. (2008). The NPB/NPW Neuropeptide System and Its Role in Regulating Energy Homeostasis, Pain, and Emotion. Results and Problems in Cell Differentiation, 46: 239-56.

book chapters and multi-media presentations

  1. Seitz, A. and Ishii, M. (2020). Pituitary Apoplexy. In Shifrin, A. (Ed.) Endocrine Emergencies, Elsevier. in press

  2. Ishii, M. (2017). Endocrine emergencies with neurologic manifestations, Continuum Audio, Vol. 6, Issue 9

  3. Ishii, M. (2016). Thyroid Disease. In Johnston, M., Adams, H., and Fatemi, A. (Eds.), Neurobiology of Disease 2nd Edition, Oxford University Press

  4. Ishii, M. (2014). Neurologic Complications of Non-diabetic Endocrine Disorders, Continuum Audio, Vol. 03, Number 09, May 7, 2014.

    http://www.audio-digest.org/CME-Summary/continuum-audio/CA0309/SYSTEMIC-DISEASE-PART-1