Bio

Honors & Awards


  • Young Scientist award, National Conference on Biodiversity, Nature and Natural resources (2010)

Professional Education


  • Bachelor of Science, University Of Pune (2009)
  • MSc, University of Sheffield, UK, Molecular Medicine (Hons. Neuroscience) (2010)
  • PhD, Italian Institute of Technology, Italy, Developmental Neuroscience (2015)

Stanford Advisors


Publications

All Publications


  • Patterning inconsistencies restrict the true potential of dopaminergic neurons derived from human induced pluripotent stem cells. Neural regeneration research Mahajani, S., Bähr, M., Kügler, S. 2021; 16 (4): 692–93

    View details for DOI 10.4103/1673-5374.295316

    View details for PubMedID 33063729

  • Homogenous generation of dopaminergic neurons from multiple hiPSC lines by transient expression of transcription factors CELL DEATH & DISEASE Mahajani, S., Raina, A., Fokken, C., Kugler, S., Baehr, M. 2019; 10: 898

    Abstract

    A major hallmark of Parkinson's disease is loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). The pathophysiological mechanisms causing this relatively selective neurodegeneration are poorly understood, and thus experimental systems allowing to study dopaminergic neuron dysfunction are needed. Induced pluripotent stem cells (iPSCs) differentiated toward a dopaminergic neuronal phenotype offer a valuable source to generate human dopaminergic neurons. However, currently available protocols result in a highly variable yield of dopaminergic neurons depending on the source of hiPSCs. We have now developed a protocol based on HBA promoter-driven transient expression of transcription factors by means of adeno-associated viral (AAV) vectors, that allowed to generate very consistent numbers of dopaminergic neurons from four different human iPSC lines. We also demonstrate that AAV vectors expressing reporter genes from a neuron-specific hSyn1 promoter can serve as surrogate markers for maturation of hiPSC-derived dopaminergic neurons. Dopaminergic neurons differentiated by transcription factor expression showed aggravated neurodegeneration through α-synuclein overexpression, but were not sensitive to γ-synuclein overexpression, suggesting that these neurons are well suited to study neurodegeneration in the context of Parkinson's disease.

    View details for DOI 10.1038/s41419-019-2133-9

    View details for Web of Science ID 000499743800002

    View details for PubMedID 31776327

    View details for PubMedCentralID PMC6881336

  • Lamin B1 levels modulate differentiation into neurons during embryonic corticogenesis SCIENTIFIC REPORTS Mahajani, S., Giacomini, C., Marinaro, F., Tonelli, D., Contestabile, A., Gasparini, L. 2017; 7: 4897

    Abstract

    Lamin B1, a key component of the nuclear lamina, plays an important role in brain development. Ablation of endogenous Lamin B1 (Lmnb1) in the mouse strongly impairs embryonic brain development and corticogenesis. However, the mechanisms underlying these neurodevelopmental effects are unknown. Here, we report that Lamin B1 levels modulate the differentiation of murine neural stem cells (NSCs) into neurons and astroglial-like cells. In vitro, endogenous Lmnb1 depletion favors NSC differentiation into glial fibrillar acidic protein (GFAP)-immunoreactive cells over neurons, while overexpression of human Lamin B1 (LMNB1) increases the proportion of neurons. In Lmnb1-null embryos, neurogenesis is reduced, while in vivo Lmnb1 silencing in mouse embryonic brain by in utero electroporation of a specific Lmnb1 sh-RNA results in aberrant cortical positioning of neurons and increased expression of the astrocytic marker GFAP in the cortex of 7-day old pups. Together, these results indicate that finely tuned levels of Lamin B1 are required for NSC differentiation into neurons, proper expression of the astrocytic marker GFAP and corticogenesis.

    View details for DOI 10.1038/s41598-017-05078-6

    View details for Web of Science ID 000404970900059

    View details for PubMedID 28687747

    View details for PubMedCentralID PMC5501862

  • Dopamine promotes the neurodegenerative potential of beta-synuclein JOURNAL OF NEUROCHEMISTRY Raina, A., Leite, K., Guerin, S., Mahajani, S. U., Chakrabarti, K. S., Voll, D., Becker, S., Griesinger, C., Baehr, M., Kuegler, S. 2020

    Abstract

    A contribution of α-Synuclein (α-Syn) to etiology of Parkinson´s disease (PD) and Dementia with Lewy bodies (DLB) is currently undisputed, while the impact of the closely related β-Synuclein (β-Syn) on these disorders remains enigmatic. β-Syn has long been considered to be an attenuator of the neurotoxic effects of α-Syn, but in a rodent model of PD β-Syn induced robust neurodegeneration in dopaminergic neurons of the substantia nigra. Given that dopaminergic nigral neurons are selectively vulnerable to neurodegeneration in PD, we now investigated if dopamine can promote the neurodegenerative potential of β-Syn. We show that in cultured rodent and human neurons a dopaminergic neurotransmitter phenotype substantially enhanced β-Syn-induced neurodegeneration, irrespective if dopamine is synthesized within neurons or up-taken from extracellular space. Nuclear magnetic resonance interaction and thioflavin-T incorporation studies demonstrated that dopamine and its oxidized metabolites 3,4-dihydroxyphenylacetaldehyde (DOPAL) and dopaminochrome (DCH) directly interact with β-Syn, thereby enabling structural and functional modifications. Interaction of DCH with β-Syn inhibits its aggregation, which might result in increased levels of neurotoxic oligomeric β-Syn. Since protection of outer mitochondrial membrane integrity prevented the additive neurodegenerative effect of dopamine and β-Syn, such oligomers might act at a mitochondrial level similar to what is suggested for α-Syn. In conclusion, our results suggest that β-Syn can play a significant pathophysiological role in etiology of PD through its interaction with dopamine metabolites and thus should be re-considered as a disease-relevant factor, at least for those symptoms of PD that depend on degeneration of nigral dopaminergic neurons.

    View details for DOI 10.1111/jnc.15134

    View details for Web of Science ID 000564576000001

    View details for PubMedID 32730640

  • Neuronal Trans-differentiation by Transcription Factors Ascl1 and Nurr1: Induction of a Dopaminergic Neurotransmitter Phenotype in Cortical GABAergic Neurons. Molecular neurobiology Raina, A., Mahajani, S., Bähr, M., Kügler, S. 2020; 57 (1): 249–60

    Abstract

    Neurons with a desired neurotransmitter phenotype can be differentiated from induced pluripotent stem cells or from somatic cells only through tedious protocols with relatively low yield. Readily available cortical neurons isolated from embryonic rat brain, which have already undergone a complete neuronal differentiation process, might serve as alternative template source. These cultures consist of 85% glutamatergic and 15% GABAergic neurons, and we attempted to trans-differentiate them into dopaminergic neurons. Transcription factors Nurr1, Lmx1A and Pitx3, essential determinants of a dopaminergic cell fate during CNS development, were not sufficient to induce tyrosine hydroxylase expression in a significant number of cells. Combining Nurr1 with the generic neuronal differentiator and re-programming factor Ascl1, however, resulted in generation of neurons which express dopaminergic markers TH, AADC, VMAT2 and DAT. Only neurons of GABAergic phenotype could be trans-differentiated towards a dopaminergic neurotransmitter phenotype, while for glutamatergic neurons, this process proved to be neurotoxic. Intriguingly, GABAergic neurons isolated from embryonal midbrain could not be trans-differentiated into dopaminergic neurons by Ascl1 and Nurr1. Thus, in principle, post-mitotic embryonal neurons can serve as templates for neurons with a desired neurotransmitter phenotype. However, neurotransmitter phenotype plasticity critically depends on the differentiation history of the template neurons, which can result in relatively low yields of dopaminergic neurons.

    View details for DOI 10.1007/s12035-019-01701-x

    View details for PubMedID 31317490

  • Lamin B1 protein is required for dendrite development in primary mouse cortical neurons. Molecular biology of the cell Giacomini, C., Mahajani, S., Ruffilli, R., Marotta, R., Gasparini, L. 2016; 27 (1): 35–47

    Abstract

    Lamin B1, a key component of the nuclear lamina, plays an important role in brain development and function. A duplication of the human lamin B1 (LMNB1) gene has been linked to adult-onset autosomal dominant leukodystrophy, and mouse and human loss-of-function mutations in lamin B1 are susceptibility factors for neural tube defects. In the mouse, experimental ablation of endogenous lamin B1 (Lmnb1) severely impairs embryonic corticogenesis. Here we report that in primary mouse cortical neurons, LMNB1 overexpression reduces axonal outgrowth, whereas deficiency of endogenous Lmnb1 results in aberrant dendritic development. In the absence of Lmnb1, both the length and complexity of dendrites are reduced, and their growth is unresponsive to KCl stimulation. This defective dendritic outgrowth stems from impaired ERK signaling. In Lmnb1-null neurons, ERK is correctly phosphorylated, but phospho-ERK fails to translocate to the nucleus, possibly due to delocalization of nuclear pore complexes (NPCs) at the nuclear envelope. Taken together, these data highlight a previously unrecognized role of lamin B1 in dendrite development of mouse cortical neurons through regulation of nuclear shuttling of specific signaling molecules and NPC distribution.

    View details for DOI 10.1091/mbc.E15-05-0307

    View details for PubMedID 26510501

    View details for PubMedCentralID PMC4694760

  • Role of Lamin B1 in structuring the cell nucleus in eukaryotic cells. Marotta, R., Catelani, T., Pesce, M., Giacomini, C., Mahajani, S., Gasparini, L. 2016: 2
  • Lactobacillus plantarum Shows More Probiotic Potential than S. cremoris JOURNAL OF PURE AND APPLIED MICROBIOLOGY Wakhloo, D., Mahajani, S., Tembe, P., Raut, A. 2013; 7 (1): 565–70
  • Effects of antiepileptic drugs on hippocampal neurons coupled to micro-electrode arrays. Frontiers in neuroengineering Colombi, I., Mahajani, S., Frega, M., Gasparini, L., Chiappalone, M. 2013; 6: 10

    Abstract

    Hippocampal networks exhibit spontaneous electrophysiological activity that can be modulated by pharmacological manipulation and can be monitored over time using Micro-Electrode Arrays (MEAs), devices composed by a glass substrate and metal electrodes. The typical mode of activity of these dissociated cultures is the network-wide bursting pattern, which, if properly chemically modulated, can recall the ictal events of the epileptic phenotypes and is well-suited to study the effects of antiepileptic compounds. In this paper, we analyzed the changes induced by Carbamazepine (CBZ) and Valproate (VPA) on mature networks of hippocampal neurons in "control" condition (i.e., in the culturing medium) and upon treatment with the pro-convulsant bicuculline (BIC). We found that, in both control and BIC-treated networks, high doses (100 μM-1 mM) of CBZ almost completely suppressed the spiking and bursting activity of hippocampal neurons. On the contrary, VPA never completely abolish the electrophysiological activity in both experimental designs. Interestingly, VPA cultures pre-treated with BIC showed dual effects. In fact, in some cultures, at low VPA concentrations (100 nM-1 μM), we observed decreased firing/bursting levels, which returned to values comparable to BIC-evoked activity at high VPA concentrations (100 μM-1 mM). In other cultures, VPA reduced BIC-evoked activity in a concentration-independent manner. In conclusion, our study demonstrates that MEA-coupled hippocampal networks are responsive to chemical manipulations and, upon proper pharmacological modulation, might provide model systems to detect acute pharmacological effects of antiepileptic drugs.

    View details for DOI 10.3389/fneng.2013.00010

    View details for PubMedID 24312049

    View details for PubMedCentralID PMC3832899

  • Biodiesel Production from Algae Exposed to Stressful Conditions JOURNAL OF PURE AND APPLIED MICROBIOLOGY Mahajani, S., Chavan, S., Mahajani, S., Raman, V. K. 2010; 4 (1): 339–42

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