TY - JOUR
T1 - Inhibition of neutral sphingomyelinase 2 reduces extracellular vesicle release from neurons, oligodendrocytes, and activated microglial cells following acute brain injury
AU - Tallon, Carolyn
AU - Picciolini, Silvia
AU - Yoo, Seung‐Wan W.
AU - Thomas, Ajit G.
AU - Pal, Arindom
AU - Alt, Jesse
AU - Carlomagno, Cristiano
AU - Gualerzi, Alice
AU - Rais, Rana
AU - Haughey, Norman J.
AU - Bedoni, Marzia
AU - Slusher, Barbara S.
N1 - Funding Information:
The authors of this manuscript have been supported by NIH grants P30MH075673 (N.H. and B.S.S) and R01AG059799 (B.S.S.) and a Tau Pipeline Enabling grant T-PEP-18-579974C jointly funded by the Alzheimer's Association and Rainwater Charitable Foundation (to B.S.S) and by the Italian Ministry of Health (Ricerca Corrente 2020) to IRCCS Fondazione Don Carlo Gnocchi ONLUS (M.B.). The TEM analysis was carried out in ALEMBIC, an advanced microscopy laboratory at IRCCS Ospedale San Raffaele and Università Vita-Salute San Raffaele (Milan, Italy). Graphical abstract was created with BioRender.com.
Publisher Copyright:
© 2021
PY - 2021/12
Y1 - 2021/12
N2 - Extracellular Vesicles (EVs) are implicated in the spread of pathogenic proteins in a growing number of neurological diseases. Given this, there is rising interest in developing inhibitors of Neutral Sphingomyelinase 2 (nSMase2), an enzyme critical in EV biogenesis. Our group recently discovered phenyl(R)‐(1‐(3‐(3,4‐dimethoxyphenyl)‐2,6‐dimethylimidazo[1,2‐b]pyridazin‐8‐yl)pyrrolidin‐3‐yl)carbamate (PDDC), the first potent, selective, orally-available, and brain-penetrable nSMase2 inhibitor, capable of dose-dependently reducing EVs release in vitro and in vivo. Herein, using multiplexed Surface Plasmon Resonance imaging (SPRi), we evaluated which brain cell-derived EVs were affected by PDDC following acute brain injury. Mice were fed PDDC-containing chow at doses which gave steady PDDC brain exposures exceeding its nSMase2 IC50. Mice were then administered an intra-striatal IL-1β injection and two hours later plasma and brain were collected. IL-1β injection significantly increased striatal nSMase2 activity which was completely normalized by PDDC. Using SPRi, we found that IL-1β-induced injury selectively increased plasma levels of CD171 + and PLP1 + EVs; this EV increase was normalized by PDDC. In contrast, GLAST1 + EVs were unchanged by IL-1β or PDDC. IL-1β injection selectively increased EVs released from activated versus non-activated microglia, indicated by the CD11b+/IB4 + ratio. The increase in EVs from CD11b + microglia was dramatically attenuated with PDDC. Taken together, our data demonstrate that following acute injury, brain nSMase2 activity is elevated. EVs released from neurons, oligodendrocytes, and activated microglial are increased in plasma and inhibition of nSMase2 with PDDC reduced these IL-1β-induced changes implicating nSMase2 inhibition as a therapeutic target for acute brain injury.
AB - Extracellular Vesicles (EVs) are implicated in the spread of pathogenic proteins in a growing number of neurological diseases. Given this, there is rising interest in developing inhibitors of Neutral Sphingomyelinase 2 (nSMase2), an enzyme critical in EV biogenesis. Our group recently discovered phenyl(R)‐(1‐(3‐(3,4‐dimethoxyphenyl)‐2,6‐dimethylimidazo[1,2‐b]pyridazin‐8‐yl)pyrrolidin‐3‐yl)carbamate (PDDC), the first potent, selective, orally-available, and brain-penetrable nSMase2 inhibitor, capable of dose-dependently reducing EVs release in vitro and in vivo. Herein, using multiplexed Surface Plasmon Resonance imaging (SPRi), we evaluated which brain cell-derived EVs were affected by PDDC following acute brain injury. Mice were fed PDDC-containing chow at doses which gave steady PDDC brain exposures exceeding its nSMase2 IC50. Mice were then administered an intra-striatal IL-1β injection and two hours later plasma and brain were collected. IL-1β injection significantly increased striatal nSMase2 activity which was completely normalized by PDDC. Using SPRi, we found that IL-1β-induced injury selectively increased plasma levels of CD171 + and PLP1 + EVs; this EV increase was normalized by PDDC. In contrast, GLAST1 + EVs were unchanged by IL-1β or PDDC. IL-1β injection selectively increased EVs released from activated versus non-activated microglia, indicated by the CD11b+/IB4 + ratio. The increase in EVs from CD11b + microglia was dramatically attenuated with PDDC. Taken together, our data demonstrate that following acute injury, brain nSMase2 activity is elevated. EVs released from neurons, oligodendrocytes, and activated microglial are increased in plasma and inhibition of nSMase2 with PDDC reduced these IL-1β-induced changes implicating nSMase2 inhibition as a therapeutic target for acute brain injury.
KW - Exosomes
KW - Extracellular vesicles
KW - Microglia
KW - Neuroinflammation
KW - Neutral sphingomyelinase 2
KW - Surface plasmon resonance imaging
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U2 - 10.1016/j.bcp.2021.114796
DO - 10.1016/j.bcp.2021.114796
M3 - Article
C2 - 34678224
AN - SCOPUS:85118563691
SN - 0006-2952
VL - 194
JO - Biochemical Pharmacology
JF - Biochemical Pharmacology
M1 - 114796
ER -