Optogenetic Control of Molecular Motors and Organelle Distributions in Cells

SummaryIntracellular transport and distribution of organelles play important roles in diverse cellular functions, including cell polarization, intracellular signaling, cell survival, and apoptosis. Here, we report an optogenetic strategy to control the transport and distribution of organelles by light. This is achieved by optically recruiting molecular motors onto organelles through the heterodimerization of Arabidopsis thaliana cryptochrome 2 (CRY2) and its interacting partner CIB1. CRY2 and CIB1 dimerize within subseconds upon exposure to blue light, which requires no exogenous ligands and low intensity of light. We demonstrate that mitochondria, peroxisomes, and lysosomes can be driven toward the cell periphery upon light-induced recruitment of kinesin, or toward the cell nucleus upon recruitment of dynein. Light-induced motor recruitment and organelle movements are repeatable, reversible, and can be achieved at subcellular regions. This light-controlled organelle redistribution provides a new strategy for studying the causal roles of organelle transport and distribution in cellular functions in living cells

Clinical Evaluation of Targeted Arterial Infusion of Verapamil in the Interventional Chemotherapy of Primary Hepatocellular Carcinoma

This study evaluates the clinical effectiveness of targeted arterial infusion of verapamil in interventional treatment of primary hepatocellular carcinoma. For this purpose, in 273 patients with middle- or late-stage primary hepatocellular carcinoma, verapamil, IL-2, and chemotherapeutic agents were infused into the target tumor vasculature through femoral artery using Seldinger technique. The medications were infused as serial dilutions, and effectiveness was evaluated after two treatment cycles. Among these 273 patients, 76 cases showed clinical cure or significant improvement, 119 cases improved, 64 cases stabilized, while 14 cases progressed or deteriorated. In 238 patients, KPS score and body weights were stabilized. Regarding side effects, 99 patients (36.3%) developed leukopenia; 160 patients had gastrointestinal reactions (58.6%); 80 patients (29.3%) presented with elevated ALT/AST profile; and 65 cases (23.8%) had pyrexia; however, these side effects abated quickly. No elevations in BUN/Cr and/or allergic reactions were observed. Pre- and post-intervention cardiac function did not change in all the patients. No significant change was observed in ECG. Liver function was also improved after two cycles of treatment. It was concluded that verapamil management via targeted arterial infusion could effectively reverse the multidrug resistance in cancer cells in primary hepatocellular carcinoma patients and therefore enhanced the efficacy of chemotherapy

Strategic Approaches to Realize Sustainable Neighborhoods in Urban Renewal: A Case Study of Banan, Chongqing, China

Due to the lack of effective impact assessment, urban renewal in China is facing many challenges and dilemmas. Residents’ perceptions are important for the sustainability of urban renewal. This study evaluated the impacts of urban renewal on the economic, social, and environmental sustainability of a neighborhood via a case study of Banan, Chongqing, China. According to the analysis of the questionnaires and in-depth interviews and with local residents, Banan’s urban renewal led to both positive and negative impacts. This study proposed strategic approaches to realizing sustainable neighborhood during urban renewal in China according to impacts. Based on the analysis, strategies for creating sustainable neighborhoods during urban renewal were developed, including balancing of economic, social, and environmental interests, satisfying residents’ needs, and enhancing innovation. The impact of urban renewal in Banan was evaluated based on the economic, social, and environmental sustainability of a neighborhood, and the findings will be useful for policy makers and researchers engaged in sustainable urban renewal to refine their strategy

Effect of the inner-surface baffles on the tangential acoustic mode in the cylindrical combustor

The combustion instability in a propulsion system is a ubiquitous problem. The radial baffles usually installed on the injector faceplate eliminate the combustion instability (acoustic pressure oscillation) in the propulsion system. In this article, the longitudinal baffles are installed on the inner surface of the combustor wall to control the combustion instabilities. The first-order and second-order tangential modes are induced in the experiments. The effects of the parameters of the baffle on the acoustic pressure oscillation in the cylindrical combustor are investigated. The effect of the combustor nozzle on the tangential modes has been systematically investigated. It is concluded that the eigen-frequency and amplitude of the first-order tangential mode decline with the increase in the longitudinal baffle number and height. For the second-order tangential mode, the eigen-frequency and amplitude monotonically increase until a maximum value (four baffles), subsequently decrease with the increase in the baffle number and height. The combustor without the nozzle obtains a lower frequency than that with the nozzle, especially for the low baffle height in the combustor

Energy equilibrium analysis in the effervescent atomization

Abstract In this paper, the flow characteristics and energy equilibrium analysis of the effervescent atomization had been investigated theoretically and experimentally. The effect of the gas–liquid rate (GLR from 0.04 to 0.15) on the atomization stability was revealed. When the GLR was small, the atomization was unstable. The atomization was gradually stable with an increase in the GLR. The optimal atomization region can be obtained. The Sauter mean diameter (SMD) of the droplets was measured by the phase Doppler analyzer. The SMD decreases with an increase in the GLR. The energy equilibrium analysis was investigated for the swirl atomizer theoretically and experimentally. The results show that the energy dissipation terms are mainly compressed gas expansion, liquid viscosity dissipation, and resistance losses. However, the ratio of the spray kinetic energy and the surface tension energy to the total energy is small

Energy equilibrium analysis in the effervescent atomization

In this paper, the flow characteristics and energy equilibrium analysis of the effervescent atomization had been investigated theoretically and experimentally. The effect of the gas–liquid rate (GLR from 0.04 to 0.15) on the atomization stability was revealed. When the GLR was small, the atomization was unstable. The atomization was gradually stable with an increase in the GLR. The optimal atomization region can be obtained. The Sauter mean diameter (SMD) of the droplets was measured by the phase Doppler analyzer. The SMD decreases with an increase in the GLR. The energy equilibrium analysis was investigated for the swirl atomizer theoretically and experimentally. The results show that the energy dissipation terms are mainly compressed gas expansion, liquid viscosity dissipation, and resistance losses. However, the ratio of the spray kinetic energy and the surface tension energy to the total energy is small

The Dual Characteristics of Light-Induced Cryptochrome 2, Homo-oligomerization and Heterodimerization, for Optogenetic Manipulation in Mammalian Cells

The photoreceptor cryptochrome 2 (CRY2) has become a powerful optogenetic tool that allows light-inducible manipulation of various signaling pathways and cellular processes in mammalian cells with high spatiotemporal precision and ease of application. However, it has also been shown that the behavior of CRY2 under blue light is complex, as the photoexcited CRY2 can both undergo homo-oligomerization and heterodimerization by binding to its dimerization partner CIB1. To better understand the light-induced CRY2 activities in mammalian cells, this article systematically characterizes CRY2 homo-oligomerization in different cellular compartments, as well as how CRY2 homo-oligomerization and heterodimerization activities affect each other. Quantitative analysis reveals that membrane-bound CRY2 has drastically enhanced oligomerization activity compared to that of its cytoplasmic form. While CRY2 homo-oligomerization and CRY2-CIB1 heterodimerization could happen concomitantly, the presence of certain CIB1 fusion proteins can suppress CRY2 homo-oligomerization. However, the homo-oligomerization of cytoplasmic CRY2 can be significantly intensified by its recruitment to the membrane via interaction with the membrane-bound CIB1. These results contribute to the understanding of the light-inducible CRY2-CRY2 and CRY2-CIB1 interaction systems and can be used as a guide to establish new strategies utilizing the dual optogenetic characteristics of CRY2 to probe cellular processes

Optical activation of TrkA signaling

Nerve growth factor/tropomyosin receptor kinase A (NGF/TrkA) signaling plays a key role in neuronal development, function, survival, and growth. The pathway is implicated in neurodegenerative disorders including Alzheimer's disease, chronic pain, inflammation, and cancer. NGF binds the extracellular domain of TrkA, leading to the activation of the receptor's intracellular kinase domain. TrkA signaling is highly dynamic, thus mechanistic studies would benefit from a tool with high spatial and temporal resolution. Here we present the design and evaluation of four strategies for light-inducible activation of TrkA in the absence of NGF. Our strategies involve the light-sensitive protein Arabidopsis cryptochrome 2 (CRY2) and its binding partner CIB1. We demonstrate successful recapitulation of native NGF/TrkA functions by optical induction of plasma membrane recruitment and homo-interaction of the intracellular domain of TrkA. This approach activates PI3K/AKT and Raf/ERK signaling pathways, promotes neurite growth in PC12 cells, and supports the survival of dorsal root ganglion neurons in the absence of NGF. This ability to activate TrkA using light bestows high spatial and temporal resolution for investigating NGF/TrkA signaling. During embryonic development, nerve growth factor (NGF) plays a critical role in supporting neuronal differentiation, survival, and plasticity 1. In adults, NGF supports neural maintenance and repair, and deficits in NGF signaling have been implicated in several neurodegenerative disorders including Alzheimer's and Parkinson's diseases 2-4. Aberrantly elevated activity of NGF is also involved in chronic inflammatory and. CC-BY-NC-ND 4.0 International license It is made available under a (which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity