We are interested in how specific cell types of the central nervous system are generated and how they are maintained. We are mostly focusing on neurons using dopamine as their neurotransmitter, and are unraveling the signaling and transcriptional regulation that govern the specification, differentiation and maintenance of these cells. Our studies have resulted in the identification of several transcription factors with key roles in these processes. The projects are focused on understanding functions in both early specification events and in the maintenance of dopamine neurons in the adult brain. Moreover, we are also interested in regenerative medicine in relation to Parkinson’s disease and other brain disorders.
Tiklova K, Björklund A, Lahti L, Fiorenzano A, Nolbrant S, Gillberg L, Volakakis N, Yokota C, Hilschner M, Hauling T, Holmström F, Joodmardi E, Nilsson M, Parmar M, Perlmann T. 2019. Single-Cell RNA Sequencing Reveals Midbrain Dopamine Neuron Diversity Emerging During Mouse Brain Development. Nat. Comm.
In this project we aimed to understand the maturation of post mitotic mDA precursors to adult mDA neurons. We collected Pitx3-eGFP+ mDA neurons from both embryonic, early postnatal, and adult (P90) mouse for single cell RNAseq. The results revealed seven subtypes of Pitx3-eGFP+ neurons in the postnatal brain, two of which appeared to be non-dopaminergic. We also mapped the location of these subtypes using both traditional ISH combined with IHC, and a multiplex ISH approach hybridising 49 different markers simultaneously. We could see that the sublineages emerge already during embryogenesis, and a comparison to human embryos indicated that many of these subtypes can be found in the human embryonic brain. Together these results should provide a useful resource to more detailed functional studies of the mDA neuronal subtypes.
Kee N, Volakakis N, Kirkeby A, Dahl L, Storvall H, Nolbrant S, Lahti L, Björklund A, Gillberg L, Joodmardi E, Sandberg R, Parmar M, Perlmann T. 2017. Single-Cell Analysis Reveals a Close Relationship between Differentiating Dopamine and Subthalamic Nucleus Neuronal Lineages. Cell Stem Cell.
Understanding the development of midbrain dopamine (mDA) neurons is critical for improving strategies to use these cells in cell replacement therapies for Parkinson’s disease. To analyze molecular characteristics of mDA progenitors and early postmitotic precursors we sequenced their transcriptomes at a single cell level. We used a transgenic mouse line, which has eGFP inserted in the Lmx1a locus, to purify these progenitors and precursors from midgestational mouse embryos. The results revealed a close developmental relationship between midbrain dopaminergic neurons and neighbouring glutamatergic neurons of the subthalamic nucleus. We also discovered a set of distinct transcription factors which are differentially expressed between these lineages. This information can be used to refine current stem cell engineering protocols, enabling the enrichment of correctly patterned midbrain dopamine neurons in the culture.
Laguna A, Schintu N, Nobre A, Alvarsson A, Volakakis N, Jacobsen JK, Gómez-Galán M, Sopova E, Joodmardi E, Yoshitake T, Deng Q, Kehr J, Ericson J, Svenningsson P, Shupliakov O, Perlmann T. 2015. Dopaminergic control of autophagic-lysosomal function implicates Lmx1b in Parkinson’s disease. Nat Neurosci.
Transcription factors Lmx1a and Lmx1b are needed for the early specification of midbrain dopamine neurons. In this work we conditionally inactivated these factors in the postmitotic dopamine neurons using Dat-Cre. The double conditional mutants showed a loss of dopamine neurons, abnormal nerve terminals and impaired autophagic-lysosomal pathway. These effects were mainly due to the loss of Lmx1b. Moreover, in the brain samples from patients with Parkinson’s disease, LMX1B expression was decreased. Taken together, these results suggest that Lmx1b is needed for the maintenance and function of midbrain neurons, and that its downregulation may is associated with Parkinson’s disease.
Panman L, Papathanou M, Laguna A, Oosterveen T, Volakakis N, Acampora D, et al. 2014. Sox6 and Otx2 control the specification of substantia nigra and ventral tegmental area dopamine neurons.
Very little is known about how different subtypes of midbrain dopamine neurons are specified. Here we identified transcription factors Sox6, Otx2, and Nolz1 as important definers between substantia nigra (SN) and ventral tegmental area (VTA) dopamine neurons. They are expressed in different mDA progenitor populations, and after the cell-cycle exit, Sox6 is enriched in the SN neurons whereas Otx2 and Nolz1 are confined to VTA. Loss of Sox6 leads to diminished expression of SN markers and expansion of VTA markers, whereas the loss of Otx2 and Nolz1 has an opposite effect. In post-mortem brain samples from Parkinson’s disease patients, Sox6 levels are reduced. These results indicate that Sox6 is a determinant for SN neurons, which in turn could be used in stem cell engineering strategies to replace lost SN neurons in Parkinson’s disease.
Kadkhodaei B, Alvarsson A, Schintu N, Ramsköld D, Volakakis N, Joodmardi E, Yoshitake T, Kehr J, Decressac M, Björklund A, Sandberg R, Svenningsson P, Perlmann T. 2013. Transcription factor Nurr1 maintains fiber integrity and nuclear-encoded mitochondrial gene expression in dopamine neurons. Proc. Natl. Sci., USA
Transcription factor Nurr1, essential for the development of midbrain dopamine neurons, has also been associated with Parkinson’s disease. To understand whether Nurr1 plays a role in the maintenance and function of postnatal dopamine neurons, we conditionally inactivated it using inducible Dat-CreERT2. Although the loss of Nurr1 in the postnatal stage did not lead to any major loss of dopamine neurons themselves, their dopamine fibers appeared abnormal. Furthermore, the mutants had less dopamine in their striatum, which resulted in problems with motor coordination. Using lasercapture microdissection, we collected dopamine neurons from the mutants and controls for RNA sequencing. This enabled us to identify a set of Nurr1-regulated genes, most of which had a function in mitochondria. These results indicate that postnatally Nurr1 has an important role in maintaining high respiratory function in dopamine neurons, and that its loss recapitulates early stages of Parkinson’s disease.
Panman L, Andersson E, Alekseenko Z, Hedlund E, Kee N, Mong J, Uhde CW, Deng Q, Sandberg R, Stanton LW, Ericson J, Perlmann T. 2011.
Transcription factor-induced lineage selection of stem cell-derived neural progenitor cells. Cell Stem Cell
One of the main challenges in regenerative medicine is to generate homogeneous cultures of the desired cell types. In this work we show that transcription factors Lmx1a, Phox2b, Nkx2.2, and Olig2 can induce desired neuronal identities in the stem cell derived neuronal progenitor cultures. By overexpressing these factors under Nestin enhancer, with suitable patterning factors, we were able to enrich different motoneuron (MN) types as well as serotonergic (5HT) neurons. The correct identities of the generated neurons were verified by global gene expression analyses using microarrays. These results provide a way to efficiently generate principally any type of neuron by the expression of key transcription factors in stem cells.
All publications by Thomas Perlmann