Pulsed electromagnetic fields synergize with graphene to enhance dental pulp stem cell-derived neurogenesis by selectively targeting TRPC1 channels

Abstract

Conventional root canal treatment replaces the infected pulp with defined materials. Alternative cell-based tissue engineering strategies aim to regenerate a fully functional pulp within the root canal. Despite recent advances in this area, however, the regeneration of an innervated pulp remains a major challenge in the field. Both graphene (2DG) and pulsed electromagnetic fields (PEMFs) independently have been shown to promote diverse cellular developmental programs. The present study showed that 2DG promoted the neurogenic induction of human dental pulp stem cells (hDPSCs) by upregulating and accelerating the expression of mature neuronal markers. Notably, 2DG induced the highest expression of transient receptor potential canonical cation channel type 1 (TRPC1) during early neurogenesis. As brief PEMF exposure promotes in vitro differentiation by activating a TRPC1-mitochondrial axis, an opportunity to combine 2DG with developmentally targeted PEMF exposure for synergistic effects was realizable. Neurogenic gene expression, neurotransmitter release, and reactive oxygen species (ROS) production were greatly enhanced by a brief (10 min) and low amplitude (2 mT) PEMF exposure timed to coincide with the highest TRPC1 expression from hDPSCs on 2DG. In contrast, hDPSCs on glass were less responsive to PEMF exposure. The capacity of PEMFs to promote neurogenesis was precluded by the administration of penicillin/streptomycin, mirroring previous studies demonstrating that aminoglycoside antibiotics block TRPC1-mediated calcium entry and verifying the contribution of TRPC1 in this form of magnetoreception. Hence, graphene created a more conducive environment for subsequent PEMF-stimulated neurogenic induction of hDPSCs through their mutual capacity to activate TRPC1with subsequent ROS production.

Modulated TRPC1 Expression Predicts Sensitivity of Breast Cancer to Doxorubicin and Magnetic Field Therapy: Segue Towards a Precision Medicine Approach

“…The presented combinational therapeutic strategy may hence prove more selective and safer than conventional therapies, particularly for cancers characterized by elevated TRPC1 channel expression. Finally, given the demonstrated specificity of PEMF treatment for TRPC1 expression reported here and elsewhere ( 5 , 11 , 32 , 45 ), complementation of conventional DOX-based chemotherapy by localizable PEMF exposure may serve as a method to avert collateral toxicity ( 3 ) as well as paradoxical effects ( 57 ), by allowing the lowering of dose systemically-delivered chemotherapeutic drug while maintaining a unique level of specificity for TRPC1-associated cancers. The potential value of these unique combination of features merit future investigation and clinical validation.…”

“…PEMF exposure stimulates ROS production in cancer ( 29 , 30 ) and non-cancer ( 5 , 31 , 32 ) cells. Underlying this response is a magnetically-responsive, TRPC1-mediated calcium entry pathway that modulates mitochondrial respiration and cell proliferation ( 5 , 32 ). By contrast, DOX increases cytoplasmic and mitochondrial ROS by disrupting mitochondrial redox cycling and function ( 33 ).…”

“…With reference to this study, PEMF exposure was shown to undermine MCF-7 and MDA-MB-231 cell growth ( Figures 3B, C ) in correlation with TRPC1 expression ( Figure 5E ), presumably due to the over-stimulation of this recently elucidated calcium-mitochondrial axis ( Figure 4H ) ( 5 , 11 ). Previously it was shown that magnetosensitivity and downstream mitochondrial responses correlate with TRPC1 developmental expression and function ( 5 , 11 , 32 , 45 ), whereas other common TRP channels did not show such a strong correlation ( 5 , 32 , 45 ). Moreover, the genetic silencing of TRPM7 ( 5 ), the most highly and ubiquitously expressed of all TRP channels ( 18 ), was unable to preclude magnetic sensitivity, whereas the genetic silencing of TRPC1 alone was capable of negating magnetic responsiveness.…”

“…Finally, selective vesicular delivery of TRPC1 to cells genetically-engineered to be deficient in TRPC1 expression was sufficient to reinstate Magnetic Mitohormesis ( 5 , 11 ). The magnetic sensitivity conferred by TRPC1 and its relevance to mitohormetic survival mechanisms ( 5 , 11 , 32 ) makes it a valuable target for clinical exploitation in cancer treatment ( 34 ).…”

Magnetic mitohormesis: A non-invasive therapy for inflammatory disorders?

“…Low amplitude and extremely low-frequency pulsed electromagnetic fields (PEMFs) were shown capable of inducing mitochondrial respiration and mitohormetic responses in muscle, both in vitro (Yap et al, 2019) and in vivo (Tai et al, 2020), downstream of PGC-1α activation. The employed Helmholtz coil systems create a three-dimensional volume of field uniformity (Crocetti et al, 2013;Wong et al, 2022) that is essential for achieving optimal biological efficacy (Parate et al, 2017;Yap et al, 2019;Madanagopal et al, 2021). Muscle was found to be most responsive to PEMFs at an amplitude of 1.5 milliTesla (mT) delivered once a week for 10 min (Yap et al, 2019), whereas smaller or greater amplitude PEMFs, shorter or longer duration, or more frequent exposures, did not render additional benefits or were even less effective.…”