Patient-specific model of adipose-brain axis dysregulation in SPG11 hereditary spastic paraplegias

Martin Regensburger, MD and Tatyana Pismenyuk, MSc
Department of Stem Cell Biology (Head: Prof. Dr. Beate Winner), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany

Die sogenannten Adipozytokine sind verschiedene Hormone, die von Fettgewebe produziert werden und Informationen über Energiereserven des Körpers an das Gehirn zurückmelden. Es mehren sich Hinweise, dass Adipozytokine auch eine Rolle bei degenerativen Erkrankungen des Nervensystems spielen, wie z.B. bei der Alzheimer-Erkrankung oder der multiplen Sklerose. Unsere vorläufigen Ergebnisse deuten auf Veränderungen der Adipozytokine auch bei der hereditären spastischen Paraplegie, die durch Mutationen im SPG11-Gen verursacht wird, hin. Unsere Hypothese lautet daher, dass eine veränderte Wirkung der Adipozytokine bei der SPG11 zum Untergang der Nervenzellen beiträgt. Daher analysieren wir in diesem Projekt, ob Adipozytokine eine positive Wirkung auf Nervenzellen haben, die wir aus Hautzellen von SPG11-Patienten gewonnen haben.

Auf dem Bild von links nach rechts: Tatyana Pismenyuk, Prof. Dr. Beate Winner, Fabian Güner, Sandra Loskarn, Tania Rizo, Dr. Martin Regensburger

final report

During the second half of our project, we have gathered interesting results characterizing the role of adipocytokines in SPG11 hereditary spastic paraplegia. In our model of cortical neurons derived from patient-specific induced pluripotent stem cells (iPSC), levels of adipocytokine receptors have been analyzed. We resolved the issue of low expression levels and high interindividual variability by the generation of CRISPR/Cas9 mediated SPG11 knock out lines derived from a human embryonic stem cell line (hESC). We confirmed knock down of SPG11 by Western blot. Cortical neurons derived from SPG11 knock out hESC exhibit decreased neurite length of cortical neurons, confirming the validity of this line (Pozner et al., 2018).

Adipocytokines exert their classical function on hypothalamic neurons, by providing information about the bodily energy supplies to the brain and influencing satiety and behavior. Since the differentiation of hypothalamic neurons has recently been described in the literature (Wang et al., 2015), we applied this protocol on patient-iPSC and SPG11-hESC. Successful differentiation into hypothalamic neurons was confirmed by quantitative real-time PCR and immunohistochemistry for different subtypes of hypothalamic neurons.

Interestingly, expression of active leptin receptor isoforms was unchanged between SPG11 and control hypothalamic neurons. However, when SPG11 hypothalamic neurons were exposed to the adipocytokine leptin, our preliminary results indicate that the downstream signaling pathways JAK/ STAT were impaired. We are currently substantiating our results by additional experiments and by analyses of additional pathway components.

Based on recently published observations of lipid accumulation in SPG11 models (Branchu et al. 2017; Boutry et al. 2018; Boutry et al. 2019), we have also started analyses on intracellular lipid components in isogenic SPG11 and control cortical neurons.

In summary, our findings indicate that adipocytokine downstream signaling pathways are altered in SPG11 hypothalamic neurons – rather than a mere downregulation of receptor levels. Future experiments aim to identify underlying mechanisms and potential therapeutic targets. Moreover, intracellular lipid enzymes and components will be analyzed in these neurons.





Publication during funding period:

Pozner, T., Schray, A., Regensburger, M., Lie, D.C., Schlötzer-Schrehardt, U., Winkler, J., Turan, S., Winner, B., 2018. Tideglusib Rescues Neurite Pathology of SPG11 iPSC Derived Cortical Neurons. Front Neurosci 12, 43. doi:10.3389/fnins.2018.00914.s001



Wang, L., Meece, K., Williams, D.J., Lo, K.A., Zimmer, M., Heinrich, G., Martin Carli, J., Leduc, C.A., Sun, L., Zeltser, L.M., Freeby, M., Goland, R., Tsang, S.H., Wardlaw, S.L., Egli, D., Leibel, R.L., 2015. Differentiation of hypothalamic-like neurons from human pluripotent stem cells. J. Clin. Invest. 125, 796–808. doi:10.1172/JCI79220

Branchu, J., Boutry, M., Sourd, L., Depp, M., Leone, C., Corriger, A., Vallucci, M., Esteves, T., Matusiak, R., Dumont, M., Muriel, M.P., Santorelli, F.M., Brice, A., El Hachimi, K.H., Stevanin, G., Darios, F., 2017. Loss of spatacsin function alters lysosomal lipid clearance leading to upper and lower motor neuron degeneration. Neurobiol. Dis. 102:21–37.

Boutry, M., Branchu, J., Lustremant, C., Pujol, C., Pernelle, J., Matusiak, R., Seyer, A., Poirel, M., Chu-Van, E., Pierga, A., Dobrenis, K., Puech, J.P., Caillaud, C., Durr, A., Brice, A., Colsch, B., Mochel, F., El Hachimi, K.H., Stevanin, G., Darios, F., 2018. Inhibition of lysosome membrane recycling causes accumulation of gangliosides that contribute to neurodegeneration. Cell Rep. ;23:3813–26

Boutry M, Pierga A, Matusiak R, Branchu J, Houllegatte M, Ibrahim Y, et al. Loss of spatacsin impairs cholesterol trafficking and calcium homeostasis. Commun Biol. 2019 Oct 17;2(1):772.