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Post-paralysis tyrosine kinase inhibition with masitinib abrogates neuroinflammation and slows disease progression in inherited amyotrophic lateral sclerosis.

Trias E, Ibarburu S, Barreto-Núñez R, Babdor J, Maciel TT, Guillo M, Gros L, Dubreuil P, Díaz-Amarilla P, Cassina P, Martínez-Palma L, Moura IC, Beckman JS, Hermine O, Barbeito L - J Neuroinflammation (2016)

Bottom Line: Whether pharmacological downregulation of such aberrant glial cells will decrease motor neuron death and prolong survival is unknown.We found that masitinib selectively inhibited the tyrosine kinase receptor colony-stimulating factor 1R (CSF-1R) at nanomolar concentrations.Remarkably, masitinib significantly prolonged survival when delivered after paralysis onset, an unprecedented effect in preclinical models of ALS, and therefore appears well-suited for treating ALS.

View Article: PubMed Central - PubMed

Affiliation: Institut Pasteur de Montevideo, Mataojo 2020, Montevideo, 11.400, Uruguay.

ABSTRACT

Background: In the SOD1(G93A) mutant rat model of amyotrophic lateral sclerosis (ALS), neuronal death and rapid paralysis progression are associated with the emergence of activated aberrant glial cells that proliferate in the degenerating spinal cord. Whether pharmacological downregulation of such aberrant glial cells will decrease motor neuron death and prolong survival is unknown. We hypothesized that proliferation of aberrant glial cells is dependent on kinase receptor activation, and therefore, the tyrosine kinase inhibitor masitinib (AB1010) could potentially control neuroinflammation in the rat model of ALS.

Methods: The cellular effects of pharmacological inhibition of tyrosine kinases with masitinib were analyzed in cell cultures of microglia isolated from aged symptomatic SOD1(G93A) rats. To determine whether masitinib prevented the appearance of aberrant glial cells or modified post-paralysis survival, the drug was orally administered at 30 mg/kg/day starting after paralysis onset.

Results: We found that masitinib selectively inhibited the tyrosine kinase receptor colony-stimulating factor 1R (CSF-1R) at nanomolar concentrations. In microglia cultures from symptomatic SOD1(G93A) spinal cords, masitinib prevented CSF-induced proliferation, cell migration, and the expression of inflammatory mediators. Oral administration of masitinib to SOD1(G93A) rats starting after paralysis onset decreased the number of aberrant glial cells, microgliosis, and motor neuron pathology in the degenerating spinal cord, relative to vehicle-treated rats. Masitinib treatment initiated 7 days after paralysis onset prolonged post-paralysis survival by 40 %.

Conclusions: These data show that masitinib is capable of controlling microgliosis and the emergence/expansion of aberrant glial cells, thus providing a strong biological rationale for its use to control neuroinflammation in ALS. Remarkably, masitinib significantly prolonged survival when delivered after paralysis onset, an unprecedented effect in preclinical models of ALS, and therefore appears well-suited for treating ALS.

No MeSH data available.


Related in: MedlinePlus

Masitinib prevented microglia proliferation by inhibiting CSF-1R. a Microglia cultured from symptomatic SOD1G93A rat spinal cord in low FBS conditions (0.5 %) adding 30 ng/mL of M-CSF with indicated masitinib concentrations. The insets show the hypertrophic vacuolated cells in vehicle and M-CSF conditions and the small rounded cells after masitinib treatment (scale bars: contrast 20 μm and DAPI/BrdU 50 μm). b The graph shows the quantitative BrdU analysis where positive cells were counted and expressed as percentage of total cells stained with DAPI. M-CSF treatment produced a significant increase in microglial proliferation that was blocked by masitinib. c Kinase inhibition assay showing that masitinib inhibited CSF-1R with an IC50 = 90 ± 35 nM. All data are expressed as mean ± SEM *p < 0.01
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Fig1: Masitinib prevented microglia proliferation by inhibiting CSF-1R. a Microglia cultured from symptomatic SOD1G93A rat spinal cord in low FBS conditions (0.5 %) adding 30 ng/mL of M-CSF with indicated masitinib concentrations. The insets show the hypertrophic vacuolated cells in vehicle and M-CSF conditions and the small rounded cells after masitinib treatment (scale bars: contrast 20 μm and DAPI/BrdU 50 μm). b The graph shows the quantitative BrdU analysis where positive cells were counted and expressed as percentage of total cells stained with DAPI. M-CSF treatment produced a significant increase in microglial proliferation that was blocked by masitinib. c Kinase inhibition assay showing that masitinib inhibited CSF-1R with an IC50 = 90 ± 35 nM. All data are expressed as mean ± SEM *p < 0.01

Mentions: To determine the effect of tyrosine kinase inhibition with masitinib, we used microglia isolated from the primary spinal cord cultures of symptomatic SOD1G93A rats before their transformation into astrocyte-like cells [5]. Microglia appeared as hypertrophic phagocytic cells that actively proliferate in the presence of fetal bovine serum (FBS) or M-CSF (Fig. 1a). Treating cell cultures using pharmacological concentrations of masitinib (0.1–1 μM) dose-dependently abrogated the morphology of hypertrophic phagocytic microglia and also inhibited M-CSF-induced proliferation as measured by BrdU uptake (Fig. 1b). In accordance, masitinib potently inhibited the kinase activity of recombinant CSF-1R with an IC50 of 90 ± 35 nM (Fig. 1c), a concentration that is reachable in vivo.Fig. 1


Post-paralysis tyrosine kinase inhibition with masitinib abrogates neuroinflammation and slows disease progression in inherited amyotrophic lateral sclerosis.

Trias E, Ibarburu S, Barreto-Núñez R, Babdor J, Maciel TT, Guillo M, Gros L, Dubreuil P, Díaz-Amarilla P, Cassina P, Martínez-Palma L, Moura IC, Beckman JS, Hermine O, Barbeito L - J Neuroinflammation (2016)

Masitinib prevented microglia proliferation by inhibiting CSF-1R. a Microglia cultured from symptomatic SOD1G93A rat spinal cord in low FBS conditions (0.5 %) adding 30 ng/mL of M-CSF with indicated masitinib concentrations. The insets show the hypertrophic vacuolated cells in vehicle and M-CSF conditions and the small rounded cells after masitinib treatment (scale bars: contrast 20 μm and DAPI/BrdU 50 μm). b The graph shows the quantitative BrdU analysis where positive cells were counted and expressed as percentage of total cells stained with DAPI. M-CSF treatment produced a significant increase in microglial proliferation that was blocked by masitinib. c Kinase inhibition assay showing that masitinib inhibited CSF-1R with an IC50 = 90 ± 35 nM. All data are expressed as mean ± SEM *p < 0.01
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4940876&req=5

Fig1: Masitinib prevented microglia proliferation by inhibiting CSF-1R. a Microglia cultured from symptomatic SOD1G93A rat spinal cord in low FBS conditions (0.5 %) adding 30 ng/mL of M-CSF with indicated masitinib concentrations. The insets show the hypertrophic vacuolated cells in vehicle and M-CSF conditions and the small rounded cells after masitinib treatment (scale bars: contrast 20 μm and DAPI/BrdU 50 μm). b The graph shows the quantitative BrdU analysis where positive cells were counted and expressed as percentage of total cells stained with DAPI. M-CSF treatment produced a significant increase in microglial proliferation that was blocked by masitinib. c Kinase inhibition assay showing that masitinib inhibited CSF-1R with an IC50 = 90 ± 35 nM. All data are expressed as mean ± SEM *p < 0.01
Mentions: To determine the effect of tyrosine kinase inhibition with masitinib, we used microglia isolated from the primary spinal cord cultures of symptomatic SOD1G93A rats before their transformation into astrocyte-like cells [5]. Microglia appeared as hypertrophic phagocytic cells that actively proliferate in the presence of fetal bovine serum (FBS) or M-CSF (Fig. 1a). Treating cell cultures using pharmacological concentrations of masitinib (0.1–1 μM) dose-dependently abrogated the morphology of hypertrophic phagocytic microglia and also inhibited M-CSF-induced proliferation as measured by BrdU uptake (Fig. 1b). In accordance, masitinib potently inhibited the kinase activity of recombinant CSF-1R with an IC50 of 90 ± 35 nM (Fig. 1c), a concentration that is reachable in vivo.Fig. 1

Bottom Line: Whether pharmacological downregulation of such aberrant glial cells will decrease motor neuron death and prolong survival is unknown.We found that masitinib selectively inhibited the tyrosine kinase receptor colony-stimulating factor 1R (CSF-1R) at nanomolar concentrations.Remarkably, masitinib significantly prolonged survival when delivered after paralysis onset, an unprecedented effect in preclinical models of ALS, and therefore appears well-suited for treating ALS.

View Article: PubMed Central - PubMed

Affiliation: Institut Pasteur de Montevideo, Mataojo 2020, Montevideo, 11.400, Uruguay.

ABSTRACT

Background: In the SOD1(G93A) mutant rat model of amyotrophic lateral sclerosis (ALS), neuronal death and rapid paralysis progression are associated with the emergence of activated aberrant glial cells that proliferate in the degenerating spinal cord. Whether pharmacological downregulation of such aberrant glial cells will decrease motor neuron death and prolong survival is unknown. We hypothesized that proliferation of aberrant glial cells is dependent on kinase receptor activation, and therefore, the tyrosine kinase inhibitor masitinib (AB1010) could potentially control neuroinflammation in the rat model of ALS.

Methods: The cellular effects of pharmacological inhibition of tyrosine kinases with masitinib were analyzed in cell cultures of microglia isolated from aged symptomatic SOD1(G93A) rats. To determine whether masitinib prevented the appearance of aberrant glial cells or modified post-paralysis survival, the drug was orally administered at 30 mg/kg/day starting after paralysis onset.

Results: We found that masitinib selectively inhibited the tyrosine kinase receptor colony-stimulating factor 1R (CSF-1R) at nanomolar concentrations. In microglia cultures from symptomatic SOD1(G93A) spinal cords, masitinib prevented CSF-induced proliferation, cell migration, and the expression of inflammatory mediators. Oral administration of masitinib to SOD1(G93A) rats starting after paralysis onset decreased the number of aberrant glial cells, microgliosis, and motor neuron pathology in the degenerating spinal cord, relative to vehicle-treated rats. Masitinib treatment initiated 7 days after paralysis onset prolonged post-paralysis survival by 40 %.

Conclusions: These data show that masitinib is capable of controlling microgliosis and the emergence/expansion of aberrant glial cells, thus providing a strong biological rationale for its use to control neuroinflammation in ALS. Remarkably, masitinib significantly prolonged survival when delivered after paralysis onset, an unprecedented effect in preclinical models of ALS, and therefore appears well-suited for treating ALS.

No MeSH data available.


Related in: MedlinePlus