Search bioRxiv⌕ Search

Biology subjects

Hsieh, C.-J.

Publications and source records attributed to Hsieh, C.-J..

6 recordsLinked to original sources

Synthesizing Mechanistic Hypotheses from Single-Cell Omics via Discretized Feature Attribution and Empirical Language Model Grounding

Single-cell multimodal omics offer unprecedented resolution of cellular networks, yet translating continuous computational attributions into structured, testable biological mechanisms remains a persistent bottleneck. To address this limitation, we introduce an analytical pipeline employing decision trees to discretize continuous neural network attributions into explicit regulatory thresholds. These boundaries then structurally constrain large language models, enabling them to integrate established literature with empirical data to synthesize context-specific hypotheses. Applying this continuous-to-discrete framework across sparse datasets yielded novel biological mechanisms. Specifically, the framework articulated a cytoskeletal gating hierarchy governing EGF-stimulated pathways, identified transcriptomic drivers of input resistance in cortical interneurons, and delineated translational logic predicting Ki-67 abundance within spatial transcriptomics. Retrospective benchmarking validated the frameworks capacity to autonomously reconstruct published regulatory logic. Supported by a locally deployable open-weight language model and a code-free interface, this approach establishes an auditable methodology to extract robust experimental hypotheses from high-dimensional single-cell data.

systems biology↗

Mechanistic Language Modeling and Oxygenated 3D Screening Reveal Berberine and Enzalutamide Synergy in Resistant Prostate Cancer

Resistance to androgen receptor inhibitors remains a primary challenge in prostate cancer treatment, yet identifying synergis-tic co-therapies is hindered by immense combinatorial search spaces and the limited interpretability of predictive computation models. Here, we developed an integrated discovery-validation axis coupling knowledge-augmented large language models with oxygen-supplemented 3D spheroid assays. By leveraging inherent model stochasticity, our framework measures the degree of consensus across independent predictions to establish a formal metric for predictive accuracy. This principle enables high-throughput assessment of complex signaling crosstalk, yielding mechanistic rationales for all predictions and defining a high-confidence zone that minimizes experimental attrition. Utilizing this approach to screen 3,592 natural products, we identified a previously unrecognized synergy between berberine and enzalutamide that re-sensitizes resistant cells. Validation confirms that berberine perturbs the PI3K/AKT/mTOR and AMPK axes, a finding consistent with the mechanistic rationales computationally derived by the framework. Integrating interpretable AI with physiologically relevant 3D screening provides a scalable methodology for the rational discovery of synergistic therapies. SignificanceIntegrating mechanistic AI with oxygenated 3D screening, we identify a novel berberine-enzalutamide synergy. This framework resolves complex signaling dependencies, providing a scalable, transparent methodology for the rational discovery of effective combination therapies.

bioengineering↗

A Small-molecule Antagonist Radiotracer for Positron Emission Tomography Imaging of the Mu Opioid Receptor.

The opioid crisis is a catastrophic health emergency catalyzed by the misuse of opioids that target and activate the mu opioid receptor. Traditional radioligands used to study the mu opioid receptor are often tightly regulated owing to their abuse and respiratory depression potential. In the present study, we sought to design and characterize a library of 24 non-agonist ligands for the mu opioid receptor. Ligands were evaluated for the binding affinity, intrinsic activity, and predicted blood-brain barrier permeability. Several ligands demonstrated single-digit nM binding affinity for the mu opioid receptor while also demonstrating selectivity over the delta and kappa opioid receptors. The antagonist behavior of 1A and 3A at the mu opioid receptor indicate that these ligands would likely not induce opioid-dependent respiratory depression. Therefore, these ligands can enable a safer means to interrogate the endogenous opioid system. Based on binding affinity, selectivity, and potential off-target binding, [11C]1A was prepared via metallophotoredox of the aryl-bromide functional group to [11C]methyl iodide. The nascent radiotracer demonstrated brain uptake in a rhesus macaque model and accumulation in the caudate and putamen. Naloxone was able to reduce [11C]1A binding, though the interactions were not as pronounced as naloxones ability to displace [11C]carfentanil. These results suggest that GSK1521498 and related congeners are amenable to radioligand design and can offer a safer way to query opioid neurobiology.

neuroscience↗

ROStrace detects oxidative stress in vivo and predicts progression of Alzheimer's disease pathology in APP/PS1 mice.

PurposeOxidative stress is implicated in the pathogenesis of the most common neurodegenerative diseases, such as Alzheimers disease (AD). However, tracking oxidative stress in the brain has proven difficult and impeded its use as a biomarker. Herein, we investigate the utility of a novel positron emission tomography (PET) tracer, [18F]ROStrace, as a biomarker of oxidative stress throughout the course of AD in the well-established APP/PS1 double mutant mouse model. MethodsPET imaging studies were conducted in wild-type (WT) and APP/PS1 mice at 3 different time points, representing early (5 mo.), middle (10 mo.), and advanced (16 mo.) life (n = 6-12, per sex). Semi-quantitation SUVRs of the plateau phase (40-60min post-injection; SUVR40-60) of ten brain subregions were designated by the Mirrione atlas and analyzed by Pmod. Statistical parametric mapping (SPM) was used to distinguish brain regions with elevated ROS in APP/PS1 relative to WT in both sexes. The PET studies were validated by ex vivo autoradiography and immunofluorescence with the parent compound, dihydroethidium. Results[18F]ROStrace retention was increased in the APP/PS1 brain compared to age-matched controls by 10 mo. of age (p < 0.0001), and preceded the accumulation of oxidative damage in APP/PS1 neurons at 16mo. (p < 0.005). [18F]ROStrace retention and oxidative damages were higher and occurred earlier in female APP/PS1 mice as measured by PET (p < 0.001), autoradiography and immunohistochemistry (p < 0.05). [18F]ROStrace differences emerged mid-life, temporally and spatially correlating with increased A{beta} burden (r2 = 0.36; p = 0.0003), which was also greatest in the female brain (p < 0.001). Conclusions[18F]ROStrace identifies increased oxidative stress and neuroinflammation in APP/PS1 female mice, concurrent with increased amyloid burden mid-life. Differences in oxidative stress during this crucial time may partially explain the sexual dimorphism in AD. [18F]ROStrace may provide a long-awaited tool to stratify at-risk patients who may benefit from antioxidant therapy prior to irreparable neurodegeneration.

neuroscience↗

Poly(ADP-ribose) induces α-synuclein aggregation in neuronal-like cells andinteracts with phosphorylated α-synuclein in post mortem PD samples

BackgroundPoly (ADP-ribose) (PAR) is a negatively charged polymer that is biosynthesized by Poly (ADP-ribose) Polymerase-1 (PARP-1) and regulates various cellular processes. Alpha-synuclein (Syn) is an intrinsically disordered protein (IDP) that has been directly implicated with driving the onset and progression of Parkinsons disease (PD). The mechanisms by which Syn elicits its neurotoxic effects remain unclear. Recent findings indicate that one of the key processes driving PD pathology are oligomeric species of Syn. Furthermore, it is well established that the main components of Lewy bodies (LBs) and Lewy neurites (LNs) in PD patients are aggregated hyperphosphorylated (S129) forms of Syn (pSyn). MethodsWe used biochemical and immunofluorescence-based assays to explore if PARP-1 enzymatic product (PAR) drives the conversion of monomeric Syn into aggregated assemblies. We performed quantitative measurements using in situ proximity ligation assays (PLA) on a transgenic murine model of -synucleinopathy (M83-SNCA*A53T) and post-mortem PD/PDD patient samples to characterize PAR-pSyn interactions. Additionally, we used bioinformatic approaches and site-directed mutagenesis to identify PAR-binding regions on fibrillar Syn. ResultsOur studies show that elevated intracellular levels of PAR promote the transition of Syn into higher molecular weight forms. We report that PAR-pSyn interactions are predominant in pathological states. Moreover, we confirm that the interactions between PAR and Syn involve electrostatic forces between negatively charged PAR and lysine residues on the N-terminal region of Syn. ConclusionsPAR plays a critical role in the early stages of monomeric Syn aggregation, thereby attributing to PD pathogenesis. Based on our results, we report that PAR seeds monomeric Syn aggregation and directly interacts with phosphorylated Syn in conditions that are pathologically relevant to PD.

neuroscience↗

Labeling proteins within Drosophila embryos by combining FRET reporters, position-specific genomic integration, and GAL4-reponsive expression

Protein interaction network (PIN) or interactome has been mapped vigorously for the entire genome. We recognize, nonetheless, that such a map could illuminate profound insights had its context been revealed. We describe a scalable protein lableling method that could re-supply natural context back to the map of protein interactome. Genetically encoded fluorescent proteins, position-specific genomic integration and GAL4-responsive expression control enable labeling proteins A, B and C each with a either an eGFP, mCherry or NirFP in specified cells of optically transparent animals such as Drosophila embryos. While following multiple proteins through development and behavior, these labels offer separable pairs of Forster resonance energy transfer between proteins A and B and proteins B and C. We test and observe FRET interactions between specific protein pairs controlling cytoskeleton, nuclear signaling and cell polarity. By using our protein labeling method, it will be possible to map protein interaction network in situ -- isPIN.

developmental biology↗