Dr. Joost Heeroma, Ph.D
Author Archive

Dr. Joost Heeroma, Ph.D

Joost Heeroma, PhD, Director of Science at GH Medical

At GH Medical, we research cannabinoids, their natural role in the human body and their potential to prevent and cure diseases.

Joost runs the GH Medical website, the Chemical Analysis Facility, the Biomedical Research Laboratory and the Clinical Trials. Dr. Heeroma’s mission is to collect everything there is to know about cannabinoids, explore their role in normal pathology, their prophylactic and therapeutic potential and make this available to patients and the general public.

As a general rule, life depends on a carefully maintained balance between order and chaos. The biological feedback mechanisms that maintain this ‘homeostatic’ balance from the central theme of his research. For his MSc thesis, Joost studied the genetic network that controls cell division and thereby protects the body from degeneration on the one hand and cancer on the other. For his PhD thesis, Joost studied how brain activity regulates itself via feedback control over brain structure (Heeroma et al., 2003, 2004; Verhage et al., 2000). As a postdoctoral researcher, Joost studied how the brain employs feed forward and feedback rules to encode memories and how mutations that disrupt negative feedback on brain activity cause diseases such as epilepsy (Heeroma et al., 2009; Lamsa et al., 2005, 2007). He later employed this principle to develop genetic therapy for epilepsy (Walker et al., 2013; Wykes et al., 2012).

Now Joost studies what is possibly the greatest group of feedback regulators of all: cannabinoids. Cannabinoids take center stage in some of the most critical cellular functions; the control of cell division, control of cellular energy supply, control of immunity/self-recognition and control of neuronal network activity. As such, cannabinoids are perfect candidates to develop therapies for diseases such as cancer, Alzheimer's disease, epilepsy, depression, migraine, chronic pain, multiple sclerosis, arthritis, Crohn's disease, anorexia, obesity and many more.

GH Medical has accumulated the world’s largest genetic library of cannabis strains including several unique landraces not previously described and potentially containing, yet undiscovered, cannabinoids. Joost aims to find these cannabinoids and test them, alone and in combination, for their physiological properties and to explore their full therapeutic potential.

References:
Heeroma, J.H., Plomp, J.J., Roubos, E.W., and Verhage, M. (2003). Development of the mouse neuromuscular junction in the absence of regulated secretion. Neuroscience 120, 733–744.

Heeroma, J.H., Roelandse, M., Wierda, K., van Aerde, K.I., Toonen, R.F.G., Hensbroek, R.A., Brussaard, A., Matus, A., and Verhage, M. (2004). Trophic support delays but does not prevent cell-intrinsic degeneration of neurons deficient for munc18-1. Eur. J. Neurosci. 20, 623–634.

Heeroma, J.H., Henneberger, C., Rajakulendran, S., Hanna, M.G., Schorge, S., and Kullmann, D.M. (2009). Episodic ataxia type 1 mutations differentially affect neuronal excitability and transmitter release. Dis. Model. Mech.

Lamsa, K., Heeroma, J.H., and Kullmann, D.M. (2005). Hebbian LTP in feed-forward inhibitory interneurons and the temporal fidelity of input discrimination. Nat. Neurosci. 8, 916–924.

Lamsa, K.P., Heeroma, J.H., Somogyi, P., Rusakov, D.A., and Kullmann, D.M. (2007). Anti-Hebbian long-term potentiation in the hippocampal feedback inhibitory circuit. Science 315, 1262–1266.

Verhage, M., Maia, A.S., Plomp, J.J., Brussaard, A.B., Heeroma, J.H., Vermeer, H., Toonen, R.F., Hammer, R.E., van den Berg, T.K., Missler, M., et al. (2000). Synaptic assembly of the brain in the absence of neurotransmitter secretion. Science 287, 864–869.

Walker, M.C., Schorge, S., Kullmann, D.M., Wykes, R.C., Heeroma, J.H., and Mantoan, L. (2013). Gene therapy in status epilepticus. Epilepsia 54 Suppl 6, 43–45.

Wykes, R.C., Heeroma, J.H., Mantoan, L., Zheng, K., MacDonald, D.C., Deisseroth, K., Hashemi, K.S., Walker, M.C., Schorge, S., and Kullmann, D.M. (2012). Optogenetic and Potassium Channel Gene Therapy in a Rodent Model of Focal Neocortical Epilepsy. Sci. Transl. Med.

Research

Complex life such as ours requires tight control of factors like energy supply, cell division, brain activity and immunity to maintain our bodies’ structural and functional integrity. Failure to do results in metabolic disorders such as obesity, anorexia or diabetes, cancer or degenerative disease such as Alzheimer’s, excitability disorders such as

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