bioRxiv Science⌕ Search

Biology subjects

Lu, T.-C.

Publications and source records attributed to Lu, T.-C..

7 recordsLinked to original sources

Rapamycin Mitigates a Sex-biased Convergent Aging Trajectory

Rapamycin extends lifespan across species, yet its cell-type-specific benefits and vulnerabilities remain unclear at whole-organism scale. Here, we present the Rapamycin Fly Cell Atlas (Rapa-FCA), a whole-organism single-nucleus transcriptomic atlas of Drosophila spanning both sexes, multiple ages, 18 cell classes, and 181 cell types. Rapamycin elicited a highly heterogeneous response, with prominent effects in reproductive, digestive, and neuromuscular systems and modest responses in most neuronal populations. Across diverse tissues, we identified a rapamycin-sensitive Convergent Aging Trajectory (CAT), marked by Fkbp12 enrichment and mTORC1-linked metabolic programs, including glycolysis and lipid synthesis. CAT-high nuclei accumulated with age and were preferentially reduced by rapamycin, especially in females, consistent with stronger female lifespan extension. By integrating CAT abundance, aging-clock predictions, and nucleus-ratio changes, we mapped sex- and cell-type-specific geroprotection effects of rapamycin. Together, the Rapa-FCA provides an organism-wide framework for resolving how rapamycin reshapes cellular aging across sex, tissue, and cellular state.

developmental biology↗

Intrinsic regulation of intestinal stem cell fate and homeostasis by Tet

How developmental progenitors navigate divergent trajectories to either establish adult stem cell pools or undergo terminal differentiation remains a fundamental gap in stem cell biology. Here, we identify the well conserved Tet protein as an essential transcriptional regulator of intestinal stem cell (ISC) establishment. Developmental Tet depletion causes region-specific ISC loss and compromises adult lifespan, while adult-specific loss drives progressive stem cell exhaustion. Overexpression of Tet leads to ISC expansion in both developing and adult guts. Utilizing a comprehensive single-nucleus transcriptomic atlas spanning gut development, we demonstrate that Tet stabilizes progenitor identity by maintaining epithelial integrity, niche signaling, and fate maintenance. By defining this developmental trajectory, we reveal Tet as a critical factor that drives proper ISC maturation and maintains long-term adult epithelial homeostasis.

developmental biology↗

In-situ glial cell-surface proteomics identifies pro-longevity factors in Drosophila

Much focus has shifted towards understanding how glial dysfunction contributes to age-related neurodegeneration due to the critical roles glial cells play in maintaining healthy brain function. Cell-cell interactions, which are largely mediated by cell-surface proteins, control many critical aspects of development and physiology; as such, dysregulation of glial cell-surface proteins in particular is hypothesized to play an important role in age-related neurodegeneration. However, it remains technically difficult to profile glial cell-surface proteins in intact brains. Here, we applied a cell-surface proteomic profiling method to glial cells from intact brains in Drosophila, which enabled us to fully profile cell-surface proteomes in-situ, preserving native cell-cell interactions that would otherwise be omitted using traditional proteomics methods. Applying this platform to young and old flies, we investigated how glial cell-surface proteomes change during aging. We identified candidate genes predicted to be involved in brain aging, including several associated with neural development and synapse wiring molecules not previously thought to be particularly active in glia. Through a functional genetic screen, we identified one surface protein, DIP-{beta}, which is down-regulated in old flies and can increase fly lifespan when overexpressed in adult glial cells. We further performed whole-head single-nucleus RNA-seq and revealed that DIP-{beta} overexpression mainly impacts glial and fat cells. We also found that glial DIP-{beta} overexpression was associated with improved cell-cell communication, which may contribute to the observed lifespan extension. Our study is the first to apply in-situ cell-surface proteomics to glial cells in Drosophila, and to identify DIP-{beta} as a potential glial regulator of brain aging.

neuroscience↗

Whole organism snRNA-seq reveals systemic peripheral changes in Alzheimer's Disease fly models

Peripheral tissues become disrupted in Alzheimers Disease (AD). However, a comprehensive understanding of how the expression of AD-associated toxic proteins, A{beta}42 and Tau, in neurons impacts the periphery is lacking. Using Drosophila, a prime model organism for studying aging and neurodegeneration, we generated the Alzheimers Disease Fly Cell Atlas (AD-FCA): whole-organism single-nucleus transcriptomes of 219 cell types from adult flies neuronally expressing human A{beta}42 or Tau. In-depth analyses and functional data reveal impacts on peripheral sensory neurons by A{beta}42 and on various non-neuronal peripheral tissues by Tau, including the gut, fat body, and reproductive system. This novel AD atlas provides valuable insights into potential biomarkers and the intricate interplay between the nervous system and peripheral tissues in response to AD-associated proteins.

genetics↗

TFEB-vacuolar ATPase signaling regulates lysosomal function and microglial activation in tauopathy

Transcription factor EB (TFEB) mediates gene expression through binding to the Coordinated Lysosome Expression And Regulation (CLEAR) sequence. TFEB targets include subunits of the vacuolar ATPase (v-ATPase) essential for lysosome acidification. Single nucleus RNA-sequencing (snRNA-seq) of wild-type and PS19 (Tau) transgenic mice identified three unique microglia subclusters in Tau mice that were associated with heightened lysosome and immune pathway genes. To explore the lysosome-immune relationship, we specifically disrupted the TFEB-v-ATPase signaling by creating a knock-in mouse line in which the CLEAR sequence of one of the v-ATPase subunits, Atp6v1h, was mutated. We show that the CLEAR mutant exhibited a muted response to TFEB, resulting in impaired lysosomal acidification and activity. Crossing the CLEAR mutant with Tau mice led to higher tau pathology but diminished microglia response. These microglia were enriched in a subcluster low in mTOR and HIF-1 pathways and was locked in a homeostatic state. Our studies demonstrate a physiological function of TFEB-v-ATPase signaling in maintaining lysosomal homoeostasis and a critical role of the lysosome in mounting a microglia and immune response in tauopathy and Alzheimers disease.

neuroscience↗

Aging Fly Cell Atlas Identifies Exhaustive Aging Features at Cellular Resolution

Aging is characterized by a decline in tissue function, but the underlying changes at cellular resolution across the organism remain unclear. Here, we present the Aging Fly Cell Atlas, a single-nucleus transcriptomic map of the whole aging Drosophila. We characterize 163 distinct cell types and perform an in-depth analysis of changes in tissue cell composition, gene expression, and cell identities. We further develop aging clock models to predict the fly age and show that ribosomal gene expression is a conserved predictive factor for age. Combining all aging features, we find unique cell type-specific aging patterns. This atlas provides a valuable resource for studying fundamental principles of aging in complex organisms.

developmental biology↗

HSB-1 inhibition and HSF-1 overexpression trigger overlapping transcriptional changes to promote longevity in Caenorhabditis elegans

Heat shock factor 1 (HSF-1) is a component of the heat shock response pathway that is induced by cytoplasmic proteotoxic stress. In addition to its role in stress response, HSF-1 also acts as a key regulator of the rate of organismal aging. Overexpression of HSF-1 promotes longevity in C. elegans via mechanisms that remain less understood. Moreover, genetic ablation of a negative regulator of HSF-1, termed as heat shock factor binding protein 1 (HSB-1), results in hsf-1-dependent life span extension in animals. Here we show that in the absence of HSB-1, HSF-1 acquires increased DNA binding activity to its genomic target sequence. Using RNA-Seq to compare the gene expression profiles of the hsb-1 mutant and hsf-1 overexpression strains, we found that while more than 1,500 transcripts show [≥]1.5-fold upregulation due to HSF-1 overexpression, HSB-1 inhibition alters the expression of less than 500 genes in C. elegans. Roughly half of the differentially regulated transcripts in the hsb-1 mutant have altered expression also in hsf-1 overexpressing animals, with a strongly correlated fold-expression pattern between the two strains. In addition, genes that are upregulated via both HSB-1 inhibition and HSF-1 overexpression include numerous DAF-16 targets that have known functions in longevity regulation. This study identifies how HSB-1 acts as a specific regulator of the transactivation potential of HSF-1 in non-stressed conditions, thus providing a detailed understanding of the role of HSB-1/HSF-1 signaling pathway in transcriptional regulation and longevity in C. elegans.

genetics↗