Mid-Atlantic Section Fall Meeting 2020
Volume 65, Number 20
Friday–Sunday, December 4–6, 2020;
Virtual
Session K03: Bio-Sensing II
11:30 AM–1:30 PM,
Sunday, December 6, 2020
Chair: Yuanwei Zhang, NJIT
Abstract: K03.00002 : Mitochondria Imaging, Sensing and Photo-modulation*
12:06 PM–12:42 PM
Preview Abstract
Abstract
Author:
Kevin Belfield
(New Jersey Institute of Technology)
Mitochondria are essential targets for study and treatment of mitochondrial
dysfunction diseases such as cancer, cardiovascular and neurodegenerative
diseases. Chemoresistance is one of the major challenges for cancer
treatment, more recently ascribed to defective mitochondrial outer membrane
permeabilization (MOMP), significantly diminishing chemotherapeutic
agent-induced apoptosis. However, gaining access to the mitochondria for
either long term imaging or for selective manipulation is challenging, as
the hydrophobic inner membrane is a barrier limiting diffusive transport.
Mitochondria penetrating peptides (MPPs) are short peptides that can be
uptaken by mitochondria. We developed a novel MPP probe and evaluated its
use in long term mitochondrial imaging and trafficking. The novel MPP we
designed and prepared contained a six amino acid sequence,
D-Argine-Phenylalanine-D-Argine-Phenylalanine- D-Argine-Phenylalanine-NH2
(rFrFrF), which was subsequently conjugated to the commercially available
6-(tetramethylrhodamine-5-(and-6)-carboxamido)hexanoic acid (TAMRA)
fluorophore. The result is a novel mitochondria penetrating peptide
(TAMRA-MPP). This bioconjugate exhibited low cytotoxicity, high
biocompatibility, and long term persistence in mitochondria. This TAMRA-MPP
conjugate is a potentially valuable long-term mitochondria tracking probe
for monitoring mitochondria distribution, activities, fission, and fusion.
A boron-dipyrromethene (BODIPY) chromophore-based triarylsulfonium photoacid
generator (BD-PAG) was also created, and its ability to target mitochondria
was demonstrated with the aim to regulate mitochondrial pH and further
depolarize the mitochondrial membrane. Cell viability assays were employed
to assess the BD-PAG's dark biocompatibility, and live cell fluorescence
bioimaging indicated selective targeting of and accumulation in the
mitochondria. A number of assays were conducted that confirmed the ability
of photoactivation of BD-PAG to modulate mitochondrial pH, effecting
mitochondrial membrane depolarization. Investigations with a common
chemotherapeutic agent in which certain tumors develop resistance to
chlorambucil was studied in combination with BD-PAG, and its
photoactivation, revealed a new strategy in chemoresistance suppression.
*National Science Foundation CHE-1726345