Mesenchymal stem cells (MSCs) are multipotent cells that play an important role in tissue homeostasis and regeneration by their self-renewal and differentiation ability. Due to their natural regenerative abilities via their reconstructive and paracrine properties, they are of great interest for use in cell therapy inter alia in dermatology, neurology, cardiology, orthopedics, and immunology. MSCs can be obtained from different sources such as bone marrow, placenta, cord blood, and dental pulp, however, adipose tissue seems to be the best candidate to isolate MSCs for regenerative medicine purposes (easy, non-invasive acquisition of the patient's autologous tissue, no ethical concerns as in the case of embryonic stem cells) (Maziarz et al., 2016; Trzyna and Banaś-Ząbczyk, 2021).

Despite MSCs' great potential for regenerative medicine use, MSCs therapy has limitations such as MSCs stemness stability, heterogeneity, variable immunocompatibility, differentiation, and migratory and homing capacity. Therefore, solutions to avoid this problem are being sought, and one of them is MSCs preconditioning with biochemical and physical inducers (Ma et al., 2023; Moeinabadi-Bidgoli et al., 2023). Electromagnetic fields (EMF) preconditioning may be a precise and effective tool for controlling MSCs status, but may also be cost-effective when preparing and administering MSCs-based medical products. However, in order to modulate the fate of stem cells and achieve this goal, appropriate parameters of EMF must be selected.

Adult stem cells, including adipose-derived stem cells (ASCs), can be affected by many biochemical and biophysical stimuli in their in vivo microenvironment. The low-frequency EMF affects biological systems and can change membrane potential thus determining stem cell fate decisions by influencing the expression of specific factors, secreted proteins, proliferation, cell cycle, metabolism, stress responses, symmetric and asymmetric cell division as well as differentiation in field type-depending and time-depending manner (Maziarz et al., 2016; Baek et al., 2019; Cruciani et al., 2019; Tamrin et al., 2016; Trzyna et al., 2020).

Stem cell metabolism represents a combination and balance of intrinsic metabolic needs and extrinsic metabolic constraints (Shyh-Chang and Ng, 2017). Mitochondria, besides playing a fundamental role in energy production through oxidative phosphorylation (OxPHOS), play important roles in cell signaling by reactive oxygen species (ROS) production, calcium homeostasis, and apoptosis (Hernansanz-Agustín and Enríquez, 2021; Hock and Kralli, 2009). The EMF may reduce proton leaks, ATP-demanding processes, and mitochondrial respiratory activity thus influencing cell metabolism and stem cells' fate decision (Santini et al., 2018). Mitochondrial biogenesis and metabolic switch may be also the hallmarks of mesenchymal stem cell differentiation processes (Hong et al., 2020).

Changes in gene activation, expression, and protein secretion in cells can be triggered by epigenetic and epitranscriptomic changes such as RNA and DNA methylation during stem cell fate determination after EMF exposure (Baek et al., 2019; Tamrin et al., 2016). N6-methyladenosine (m6A) regulates RNA metabolism, numerous mRNA modifications, transcription and translation, which are necessary to control stem cell processes such as proliferation, differentiation as well as responses to heat shock, and DNA damage (Wei et al., 2022; Yu et al., 2021; Zhang et al., 2020). Also, abnormal DNA methylation can influence stem cell fate determination, and it has already been proven that EMF can inhibit the embryonic stem cell differentiation (Baek et al., 2019). Changes in epigenetic factors are reflected in the amount of various regulatory proteins such as p21 or p53 that control stem cell behavior (Kreis et al., 2019).

The purpose of this study was to investigate whether and how the EMF (50 Hz, 1.5 mT) affects the biological response of adipose-derived stem cells. Therefore, viability, cell cycle progression, stem cell membrane flexibility, mitochondrial metabolism and morphology, m6A content, expression of stem cell markers, and expression of regulatory proteins such as p21, p53, TRDMT1/DNMT2 (tRNA Aspartic Acid Methyltransferase 1, historically known as DNMT2), HSP70 (heat shock protein 70), HSP90 (heat shock protein 90), after 24 and 48 h of continuous exposure to a vertically applied sinusoidal EMF (50 Hz; 1.5 mT) in ASCs culture in vitro, were evaluated. The currently available literature, lacks comprehensive studies on the impact of EMF (50 Hz, 1.5 mT) on the biological response of ASCs, such as metabolism or epigenetic and epitranscriptomic modifications, attempting to thoroughly understand the impact of EMF on stem cell fate determination. Understanding the multi-level changes during exposure to low-frequency EMF, enriches our knowledge of the processes mobilization, adaptation, and exhaustion and their mechanisms within adipose-derived stem cells, ultimately leading to reprogramming and adoption of the stem cell “fate” (i.e. differentiation or death).