Bronchial Fibroblasts from Asthmatic Patients Display Impaired Responsiveness to Direct Current Electric Fields (dcEFs)

Abstract

Accumulating evidence suggests that an important role is played by electric signals in modifying cell behaviour during developmental, regenerative and pathological processes. However, their role in asthma has not yet been addressed. Bronchial fibroblasts have recently been identified having important roles in asthma development. Therefore, we adapted an experimental approach based on the lineages of human bronchial fibroblasts (HBF) derived from non-asthmatic (NA) donors and asthmatic (AS) patients to elucidate whether their reactivity to direct current electric fields (dcEF) could participate in the asthmatic process. The efficient responsiveness of NA HBF to an electric field in the range of 2–4 V/cm was illustrated based on the perpendicular orientation of long axes of the cells to the field lines and their directional movement towards the anode. These responses were related to the activity of TGF-β signalling, as the electrotaxis and re-orientation of NA HBF polarity was impaired by the inhibitors of canonical and non-canonical TGF-β-dependent pathways. A similar tendency towards perpendicular cell-dcEF orientation was observed for AS HBF. However, their motility remained insensitive to the electric field applied at 2–4 V/cm. Collectively, these observations demonstrate the sensitivity of NA HBF to dcEF, as well as the inter-relations between this parameter and the canonical and non-canonical TGF-β pathways, and the differences between the electrotactic responses of NA and AS HBF point to the possible role of their dcEFs in desensitisation in the asthmatic process. This process may impair the physiologic behaviour of AS HBF functions, including cell motility, ECM deposition, and contractility, thus promoting bronchial wall remodelling, which is a characteristic of bronchial asthma.

The role of TGF-β in the electrotactic reaction of mouse 3T3 fibroblasts in vitro

“…To determine the role of TGFβ in directing the migration of 3T3 cells in an electric field, we assessed the effects of inhibiting both canonical and non-canonical signaling pathways activated by TGFβ, using specific pharmacological inhibitors at concentrations validated in our previous studies ( Paw et al, 2021 ; Pavlenko et al, 2023 ). As presented in Figure 2 and Figure 3D , inhibition of the canonical Smad-dependent pathway with SB431542 did not alter the electrotaxis of 3T3 cells.…”

“…Nevertheless, our research ( Pavlenko et al, 2023 ) has shown that adult human bronchial fibroblasts respond to external electric fields by orienting themselves perpendicular to the field lines and exhibit efficient electrotaxis toward the anode. These processes depended on both canonical and non-canonical TGF-β pathways.…”

“…Our preliminary findings indicated that the prolonged response might be attributed to the relocation of the EGF receptor in the membrane of 3T3 cells. On the other hand, we have proven the involvement of TGFβ signaling in the electrotaxis of another cell type – human bronchial fibroblasts ( Pavlenko et al, 2023 ). Building on these findings, the current study delves into the role of TGFβ signaling in the long-term reaction of 3T3 fibroblasts to an electric field.…”

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“…Our preliminary findings indicated that the prolonged response might be attributed to the relocation of the EGF receptor in the membrane of 3T3 cells. On the other hand, we have proven the involvement of TGFβ signaling in the electrotaxis of another cell typehuman bronchial fibroblasts (Pavlenko et al, 2023). Building on these findings, the current study delves into the role of TGFβ signaling in the long-term reaction of 3T3 fibroblasts to an electric field.…”

“…Nevertheless, our research (Pavlenko et al, 2023) has shown that adult human bronchial fibroblasts respond to external electric fields by orienting themselves perpendicular to the field lines and exhibit efficient electrotaxis toward the anode.…”