Biology subjects

Min, D.

Publications and source records attributed to Min, D..

8 recordsLinked to original sources

bioRxiv2025

L-selectin shedding regulates functional recovery and neutrophil clearance following spinal cord injury in a sex-dependent manner

During the acute phase of spinal cord injury (SCI), neutrophils infiltrate in large numbers and can exacerbate inflammation, secondary tissue damage, and neurological deficits. L-selectin is a signaling and adhesion receptor that has been shown to facilitate neutrophil recruitment and secondary injury after SCI. During neutrophil activation, L-selectin is typically cleaved or shed from the cell surface and augmenting L-selectin shedding can improve hindlimb recovery and tissue sparing following SCI in male mice. However, it is unclear how endogenous L-selectin shedding regulates neutrophil responses and functional recovery after SCI, particularly when also considering sex as a biological variable. In this study, we investigated the sex-dependent role of endogenous L-selectin shedding in neutrophil function and long-term outcomes in a murine thoracic contusion model of SCI. We found that endogenous L-selectin shedding improves long-term functional recovery and white matter sparing in female, but not male, mice. In addition, we demonstrate that L-selectin shedding alters neutrophil accumulation in a sex-dependent manner. While L-selectin shedding does not mediate neutrophil activation or effector functions, we found that neutrophil clearance is facilitated by L-selectin shedding in female mice alone. These results demonstrate that endogenous L-selectin shedding is a critical and sex-dependent mediator of neutrophil accumulation and clearance, as well as long-term functional outcomes, after SCI.

neuroscience↗

bioRxiv2025

Single-molecule tweezers decoding hidden dimerization patterns of membrane proteins within lipid bilayers

Dimerization of transmembrane (TM) proteins is an essential biological process within cellular membranes, playing a key role in diverse pathophysiological pathways and serving as a promising therapeutic target. Although often simplified as a two-state transition from freely diffusing monomers to fully formed dimers, the dimerization process after monomer diffusion--the post-diffusion dimerization--is likely more complex due to intricate inter-residue interactions. Here, we introduce a single-molecule tweezer platform to map detailed profiles of the post-diffusion transitions in TM protein dimerization. This approach captures reversible dimerization events of a single TM dimer, revealing hidden intermediate states that emerge following the quiescent phase of monomer diffusion. Profiling the post-diffusion intermediates, kinetics, and energy landscapes--integrated with molecular dynamics simulations--uncovers the dimerization pathway, the effects of residue interactions and lipid bilayers, and the kinetic and energetic contributions of distinct dimerization domains. Furthermore, this platform characterizes selective and localized modulations via peptide binding, underscoring its potential to elucidate the mechanisms of action of TM dimer-targeting drugs at single-molecule resolution.

biophysics↗

bioRxiv2024

The CoREST-complex regulates MYC stability and promotes post-transcriptional mRNA splicing in melanoma

The CoREST complex is a multi-subunit epigenetic regulator implicated in histone modification and transcriptional repression, but its role in tumorigenesis is not well-defined. Here, we show that the CoREST complex directly interacts with and stabilizes the MYC oncoprotein in cancer cells through site-specific deacetylation of lysine residues, primarily mediated by HDAC1/2. These modifications protect MYC from proteasomal degradation independently of transcriptional regulation, maintaining high MYC protein levels in cancer cells. Transcriptomic analysis reveals that the CoREST-mediated MYC stabilization activates transcription of genes critical for DNA replication and mitotic chromosome segregation, and enhances melanoma cell viability. These findings suggest that the CoREST complex maintains cancer cell genome stability and promotes survival by sustaining MYC oncogenic activity, highlighting it as a potential therapeutic target in MYC-driven malignancies.

cancer biology↗

bioRxiv2024

Forage conservation is a neglected source of nitrous oxide

Agricultural activities are the major anthropogenic source of nitrous oxide (N2O), an important greenhouse gas and ozone-depleting substance. However, the role of forage conservation as a potential source of N2O has rarely been studied. We investigated N2O production from the simulated silage of the three major crops--maize, alfalfa, and sorghum--used for silage in the US, which comprises over 90% of the total silage production. Our findings revealed a substantial N2O could be generated, which potentially places forage conservation as the third largest N2O source in the agricultural sector. Notably, the application of chlorate as an additive significantly reduced N2O production, but neither acetylene nor intermittent exposure to oxygen showed any impact. Overall, the results highlight that denitrifiers, rather than nitrifiers, are responsible for N2O production from silage, which was confirmed by molecular analyses. Our study reveals a previously unexplored source of N2O and provides a crucial mechanistic understanding for effective mitigation strategies. Significance StatementN2O is the third most important greenhouse gas (GHG) and agriculture contributes 80% of the total anthropogenic emissions in the US. The major sources of N2O in the agricultural sector identified by the USEPA include agricultural land management, manure management, and the field burning of agricultural residues. Here, we show that forage conservation could be a significant unaccounted source of N2O, surpassing the field burning by 30. Our study provides a mechanistic understanding of N2O production and a simple and effective remedy for reducing N2O emissions. The findings have substantial implications for mitigating climate change, informing policy-makers, and guiding future research on reducing greenhouse gas emissions from livestock production.

bioengineering↗

bioRxiv2024

Hidden route of protein damage through confined oxygen gas

Oxidative modifications can severely impair protein structure, fold, and function, closely linked to human aging and diseases. Conventional oxidation pathways typically involve the free diffusion of reactive oxygen species (ROS), followed by chemical attacks on the protein surface. Here, we report a hidden route of protein oxidative damage, which we refer to as O2-confinement oxidation pathway. This pathway starts with the initial trapping of dissolved molecular oxygen (O2) within protein cavity spaces, followed by interaction with photosensitizing tryptophan residues. The trapped O2 is then converted to singlet oxygen (1O2), a powerful ROS, through spin-flip electron transfer mechanism under blue light. The generated 1O2 within the protein ultimately attacks the protein core residues through constrained diffusion, accelerating the oxidative damage. This alternative photooxidation pathway through the initial O2 trapping would bypass the antioxidant defense systems which target freely-diffusing ROS, constituting an additional layer of protein oxidative damage in cells and tissues.

biochemistry↗

bioRxiv2023

Nutlin-3a induced KRAS mutant lung cancer specific methuosis-like cell death is dependent on GFPT2

Oncogenic KRAS mutation, the most frequent mutation in non-small cell lung cancer (NSCLC), is an aggressiveness risk factor and leads to the metabolic reprogramming of cancer cells by promoting glucose, glutamine, and fatty acid absorption and glycolysis. Lately, sotorasib was approved by the FDA as a first-in-class KRAS-G12C inhibitor. However, sotorasib still has a derivative barrier, which is not effective for other KRAS mutation types, except for G12C. Additionally, resistance to sotorasib is likely to develop, demanding the need for alternative therapeutic strategies. In this study, we found that nutlin-3a, an MDM2 antagonist, inhibited the KRAS-PI3K/Akt-mTOR pathway and disrupted the fusion of both autophagosomes and macropinosomes with lysosomes. This further elucidated non-apoptotic and catastrophic macropinocytosis associated methuosis-like cell death, which was found to be dependent on GFPT2 of the hexosamine biosynthetic pathway, specifically in KRAS mutant NSCLC cells. These results indicate the potential of nutlin-3a as an alternative agent for treating KRAS mutant NSCLC cells.

cancer biology↗

bioRxiv2023

Robust single membrane protein tweezers

Single-molecule tweezers, such as magnetic tweezers, are powerful mechanical manipulation tools that can probe nm-scale structural changes in a single membrane protein under force. However, the weak molecular tethers used in the tweezers limit a long time, repetitive mechanical manipulation because of their force-induced bond breakage. Here, using the metal-free click chemistry of dibenzocyclooctyne (DBCO) cycloaddition and the rapid, strong binding of traptavidin to dual biotins (2xbiotin), we developed robust single-molecule tweezers that can perform thousands of force applications on a single membrane protein. By applying up to 50 pN for each cycle, which is sufficiently high for most biological processes, we were able to observe repetitive forced unfolding for a designer membrane protein up to approximately 1000 times on average. Monte Carlo simulations showed that the average error of the unfolding kinetic values rapidly decays to 1.8% at 200-time pulling, indicating that our method can quickly produce reliable statistics. The approach established here is also applicable to highly polar DNA molecules, permitting the nanomechanical manipulation of diverse biomolecular systems.

biophysics↗

bioRxiv2019

Development of a model estimating root length density from root impacts on a soil profile in pearl millet (Pennisetum glaucum (L.) R. Br). Application to measure root system response to water stress in field conditions

Pearl millet, unlike other cereals, is able to withstand dry and hot conditions and plays an important role for food security in arid and semi-arid areas of Africa and India. However, low soil fertility and drought constrain pearl millet yield. One of the main targets to address these constraints through agricultural practices or breeding is root system architecture. In this study, in order to easily phenotype the root system in field conditions, we developed a model to predict root length density (RLD) of pearl millet plants from root intersection densities (RID) counted on a trench profile in field conditions. We identified root orientation as an important parameter to improve the relationship between RID and RLD. Root orientation was notably found to differ between thick roots (more anisotropic with depth) and fine roots (isotropic at all depths). We used our model to study pearl millet root system response to drought and showed that pearl millet reorients its root growth toward deeper soil layers that retain more water in these conditions. Overall, this model opens ways for the characterization of the impact of environmental factors and management practices on pearl millet root system development.

plant biology↗