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Biology subjects

Moreno, T. M.

Publications and source records attributed to Moreno, T. M..

5 recordsLinked to original sources

Tumor-derived SAA1-TLR4 signaling drives tumor-to-muscle communication in pancreatic cancer cachexia

Cancer cachexia limits treatment tolerance and survival in pancreatic ductal adenocarcinoma (PDAC), yet the tumor-derived signals driving tissue dysfunction remain poorly understood. Here, we identify serum amyloid A1 (SAA1) as a mediator of tumor-to-host communication acting through Toll-like receptor 4 (TLR4). Tumor-derived SAA1 was elevated in human PDAC and in a mouse PDAC model and disrupted both myofiber and muscle stem cell (MuSC) homeostasis. Genetic reduction of tumor-derived SAA1 uncoupled tumor progression from host wasting, preserving muscle mass and function and prolonging survival without affecting primary tumor growth. Mechanistically, SAA1-TLR4 signaling drove multicellular remodeling of the skeletal muscle microenvironment. Therapeutic TLR4 inhibition after cachexia onset restored muscle mass, function and MuSC abundance and prolonged survival independently of tumor growth. Conservation of SAA1-TLR4 signaling in human skeletal muscle identifies a therapeutically actionable tumor-host pathway and demonstrates that host deterioration can be targeted independently of tumor progression.

cancer biology↗

Hormetic heat shock activates HLH-30/TFEB independently of canonical nutrient-sensing pathways

In Caenorhabditis elegans, a brief, sublethal heat shock (HS) induces a hormetic response that increases resistance to subsequent stress and extends lifespan. These benefits require hlh-30, the ortholog of mammalian transcription factor EB (TFEB). Although HS induces robust HLH-30 nuclear translocation, how this response is regulated remains poorly understood. Nutrient- and energy-sensing pathways, including mTORC1 and AMPK, regulate HLH-30/TFEB subcellular localization under other physiological conditions, but whether they mediate its nuclear translocation during HS is unknown. Here, we show that, although HS inhibited mTORC1 and dephosphorylated its conserved HLH-30 S201 target site, HLH-30 S201 phosphorylation was dispensable for HS-induced HLH-30 nuclear localization and hormetic protection. Moreover, HS remained protective in hlh-30 mutants when mTORC1 activity was reduced, revealing an HLH-30-independent component of the hormetic response. HS also activated AMPK and aak-2 was required for hormetic protection but dispensable for HS-induced HLH-30 nuclear localization and autophagosome formation. Together, these findings demonstrate that although HS engages canonical mTORC1 and AMPK signaling, these pathways do not account for HS-induced HLH-30 nuclear localization and instead make distinct contributions to hormetic protection. Our findings reveal stress-specific regulation of HLH-30/TFEB and point to additional mechanisms that drive its activation during heat stress.

cell biology↗

Autophagy flux during human aging is sex- and cell type-specific, and is associated with physical fitness

Autophagy is widely proposed to decline with age; however, direct evidence for this across cell and tissue types in humans remains limited. Furthermore, it remains unknown whether interventions that improve physiological health during aging can modify autophagic activity in humans. Here, we performed transcriptomic and functional autophagy analyses across subject-matched human cell types from a healthy aging cohort spanning the adult lifespan. RNA-seq of primary dermal fibroblasts and induced neurons (iNs) revealed increased transcription of many autophagy-related genes with age, most markedly in fibroblasts. The impact of age on autophagic activity, measured using autophagy flux assays, was cell type- and sex-dependent, and uncoupled from autophagy-gene transcription. Autophagy flux decreased with age in male fibroblasts, was unchanged in female fibroblasts, and increased in female iNs. In freshly isolated peripheral blood mononuclear cells (PBMCs), autophagy flux became more heterogeneous with age and trended higher in older individuals, independent of sex. Although autophagy flux levels did not match across different cell types, higher autophagy flux in all cell types was associated with reduced physical function in older adults ([≥]70 years). Importantly, autophagy flux decreased following 12 weeks of mild exercise in parallel with improved physical function. These findings indicate that autophagy is regulated in a cell type-, sex-and physiological function-dependent manner during human aging, and highlight PBMC autophagy flux as a potentially modifiable, blood-accessible readout of physiological state in older adults.

cell biology↗

Nucleosome stability safeguards cell identity, stress resilience and healthy aging

Nucleosomes are the minimal repeating units of chromatin. Their dynamic assembly and disassembly underpins chromatin organization and genome regulation. However, it remains unclear how intrinsic nucleosome stability contributes to higher-level yet fundamental cellular and organismal properties--such as preservation of cell identity, lineage specification, stress resilience and ultimately healthy aging. To address this, we tested the impact of decreased intrinsic nucleosome stability across multiple cell, tissue and organismal models by introducing histone mutants that weaken histone-histone interactions. While nucleosome instability did not broadly alter global chromatin accessibility, DNA damage, cell proliferation or viability, it impaired lineage-specific gene expression programs, altered lineage specification and activated intrinsic inflammatory and stress pathways in a manner reminiscent of aging in mouse tissues and human cells. Consistently, nucleosome instability accelerated the onset of age-associated transcriptional alterations and functional decline in Caenorhabditis elegans and Drosophila melanogaster, and reduced cellular resilience to exogenous perturbations-- including environmental, epigenetic and mitotic stress--in human cells and Saccharomyces cerevisiae. These cross-species findings identify nucleosome stability as an evolutionarily conserved epigenetic safeguard that preserves cell identity and stress resilience and supports organismal function and healthy aging.

genomics↗

Inhibition of early-acting autophagy genes in C. elegans neurons improves protein homeostasis, promotes exopher production, and extends lifespan via the ATG-16.2 WD40 domain

While autophagy is key to maintain cellular homeostasis, tissue-specific roles of individual autophagy genes are less understood. To study neuronal autophagy in vivo, we inhibited autophagy genes specifically in C. elegans neurons, and unexpectedly found that knockdown of early-acting autophagy genes, i.e., involved in formation of the autophagosome, except for atg-16.2, decreased PolyQ aggregates and increased lifespan, albeit independently of the degradation of autophagosomal cargo. Neuronal aggregates can be secreted from neurons via vesicles called exophers, and we found that neuronal inhibition of early-acting autophagy genes atg-7 and lgg-1/Atg8, but not atg-16.2 increased exopher formation. Moreover, atg-16.2 mutants were unable to form exophers, and atg-16.2 was required for the effects of early autophagy gene reduction on neuronal PolyQ aggregation, exopher formation, and lifespan. Notably, neuronal expression of full-length ATG-16.2 but not ATG-16.2 without a functional WD40 domain, important for non-canonical functions of ATG16L1 in mammalian cells, restored these phenotypes. Collectively, we discovered a specific role for C. elegans ATG-16.2 and its WD40 domain in exopher biogenesis, neuronal proteostasis, and lifespan determination, highlighting a possible role for non-canonical autophagy functions in both exopher formation and in aging.

cell biology↗