Functional Validation of DownRegulated MicroRNAs in HeLa Cells Treated with Polyalthia longifolia Leaf Extract Using Different Microscopic Approaches: A Morphological Alteration-Based Validation

Abstract

Several microscopy methods have been developed to assess the morphological changes in cells in the investigations of the mode of cell death in response to a stimulus. Our recent finding on the treatment of the IC50 concentration (26.67 μg/mL) of Polyalthia longifolia leaf extract indicated the induction of apoptotic cell death via the regulation of miRNA in HeLa cells. Hence, the current study was conducted to validate the function of these downregulated microRNAs in P. longifolia-treated HeLa cells using microscopic approaches. These include scanning electron microscope (SEM), transmission electron microscope (TEM), and acridine orange/propidium iodide (AO/PI)-based fluorescent microscopy techniques by observing the morphological alterations to cells after transfection with mimic miRNA. Interestingly, the morphological changes observed in this study demonstrated the apoptotic hallmarks, for instance, cell blebbing, cell shrinkage, cytoplasmic and nuclear condensation, vacuolization, cytoplasmic extrusion, and the formation of apoptotic bodies, which proved the role of dysregulated miRNAs in apoptotic HeLa cell death after treatment with the P. longifolia leaf extract. Conclusively, the current study proved the crucial role of downregulated miR-484 and miR-221-5p in the induction of apoptotic cell death in P. longifolia-treated HeLa cells using three approaches—SEM, TEM, and AO/PI-based fluorescent microscope.

Phytochemicals from Polyalthia Species: Potential and Implication on Anti-Oxidant, Anti-Inflammatory, Anti-Cancer, and Chemoprevention Activities

“…Beside the inactivation of those proliferative and pro-inflammatory signaling cascades, Shanmugapriya et al (2019 and 2020) reported that polyphenol-rich P. longifolia extracts induced HeLa cell apoptosis by down-regulation of oncogenic micro-ribonucleic acid (miRNA)-221-5p in HeLa cells [107,108]. MicroRNA is a non-coding small RNA, which consists of about 21-25 nucleotides in length and is base-pairing to the targeted messenger RNA (mRNA) [109].…”

Optical Microscopy Using the Faraday Effect Reveals in Situ Magnetization Dynamics of Magnetic Nanoparticles in Biological Samples

“…Figure shows a fluorescence amplitude image recorded at the emission wavelength of the calcein dye (green), merged with the corresponding ACS amplitude magnetic image from the same region (false color, red). Many live cells can be seen in this low magnification image, displaying a typical morphology for this cell line (see, e.g., Shanmugapriya et al). Where S1 MNPs are colocalized with live cells, they appear orange/yellow in the image (due to the overlapping color channels), whereas MNPs that have deposited onto the bottom of the cell culture holder appear red.…”

Neochamaejasmin B extracted from Stellera chamaejasme L. induces apoptosis through caspase‐10‐dependent way in insect neuronal cells

“…When AW1 cells were treated with 60 μM NCB for 24 h, typical apoptotic characteristics such as nuclear condensation and swollen mitochondria were observed (Ren et al, 2021a). When AW1 cells were treated with 80 and 100 μM NCB for 24 h, the TEM images showed apparent mitochondrial swelling (X. Wang et al, 2015) and cell shrinkage and convolution (Shanmugapriya & Sasidharan, 2019). Moreover, organelle vacuolation and apoptotic bodies were observed (L. Yang et al, 2016).…”

“…When AW1 cells were treated with 80 and 100 μM NCB for 24 h, the TEM images showed apparent mitochondrial swelling (X. Wang et al, 2015) and cell shrinkage and convolution (Shanmugapriya & Sasidharan, 2019). Moreover, organelle vacuolation and apoptotic bodies were observed (L. Yang et al, 2016).…”