Biology subjects

Craig, A. J.

Publications and source records attributed to Craig, A. J..

5 recordsLinked to original sources

bioRxiv2025

Membrane contacts between caveolae and the endoplasmic reticulum regulate uptake and metabolic trapping of long-chain fatty acids

The vital process of cellular fatty acid metabolism involves uptake, metabolic trapping and storage of long-chain fatty acids (LCFAs) in different lipid species. Although several different enzymes like transporters and acyl-CoA synthetases are involved, the sequential mechanistic steps of the process are poorly understood. Here, we have addressed the role of the caveola coat protein caveolin1 and the acyl-CoA synthetase FATP1 in the process as both have major impacts in the uptake and storage of fatty acids in vivo and in vitro. Using live cell microscopy and mass spectrometry-based quantification of LCFA metabolism, we found that FATP1-mediated uptake and metabolic processing of LCFAs is coupled to, and dependent on caveolin1. Furthermore, both proteins stimulate the incorporation of LCFA into phospholipids and triacylglycerol, but not in sphingolipids. Using correlative light and electron microscopy we found that membrane contact sites are formed between FATP1-enriched endoplasmic reticulum (ER) and caveolae. Analysis of their temporal stability showed that they are dynamic but frequently persist over minutes. We propose that caveolae directly couple the plasma membrane (PM) to the ER for directed LCFA transport and metabolic processing.

cell biology↗

bioRxiv2025

Utility of the Recombinase Driver CX3CR1::Cre Rat Strain to Evaluate Microglial Contributions to Nicotine Addiction

Smoking remains a leading preventable cause of death, and nicotine is the primary substance responsible for maintaining use of tobacco products. Preclinical rodent models have shown that neuroimmune signaling is dysregulated by nicotine self-administration (SA) within the nucleus accumbens core (NAcore), which is a key region within the mesolimbic brain reward pathway. Microglia are the resident brain immune cell and prior studies have shown that they play an important role in nicotine-related behaviors. However, while there are transgenic mouse lines that allow for specific evaluations of microglia to neurobiology and behavior, there are fewer tools available for rats as a model species thus limiting our ability to evaluate specific contributions of microglia to nicotine SA. Using transgenic rats expressing Cre under the control of the CX3CR1 promoter bred on a Long Evans (LE) background, we show that NAcore microglia can be specifically transduced with Designer Receptors Exclusively Activated by Designer Drugs (DREADDs). We further show that CX3CR1::Cre rats readily self-administer nicotine, and display a characteristic extinction curve that is not different from outbred LE or Cre-negative littermates. Together, these validation studies lay the foundation for future use of this transgenic rat line to evaluate the specific contributions of microglia in the brain to neurobehavioral underpinnings of nicotine addiction.

neuroscience↗

bioRxiv2024

ADRA2A promotes the classical/progenitor subtype and reduces disease aggressiveness of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) manifests diverse molecular subtypes, including the classical/progenitor and basal-like/squamous subtypes, with the latter known for its aggressiveness. We employed integrative transcriptome and metabolome analyses to identify potential genes contributing to the molecular subtype differentiation and its metabolic features. Transcriptome analysis in PDAC patient cohorts revealed downregulation of adrenoceptor alpha 2A (ADRA2A) in the basal-like/squamous subtype, suggesting its potential role as a candidate suppressor of this subtype. Reduced ADRA2A expression was significantly associated with a high frequency of lymph node metastasis, higher pathological grade, advanced disease stage, and decreased survival among PDAC patients. In vitro experiments demonstrated that ADRA2A transgene expression and ADRA2A agonist inhibited PDAC cell invasion. Additionally, ADRA2A-high condition downregulated the basal-like/squamous gene expression signature, while upregulating the classical/progenitor gene expression signature in our PDAC patient cohort and PDAC cell lines. Metabolome analysis conducted on the PDAC cohort and cell lines revealed that elevated ADRA2A levels were associated with suppressed amino acid and carnitine/acylcarnitine metabolism, which are characteristic metabolic profiles of the classical/progenitor subtype. Collectively, our findings suggest that heightened ADRA2A expression induces transcriptome and metabolome characteristics indicative of classical/progenitor subtype with decreased disease aggressiveness in PDAC patients. These observations introduce ADRA2A as a candidate for diagnostic and therapeutic targeting in PDAC. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=186 SRC="FIGDIR/small/584316v1_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@edc5ceorg.highwire.dtl.DTLVardef@5579b6org.highwire.dtl.DTLVardef@1a9a000org.highwire.dtl.DTLVardef@147724a_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG HighlightsO_LIADRA2A is downregulated in the basal-like/squamous PDAC while its expression is maintained in the classical/progenitor PDAC subtype C_LIO_LIUpregulated ADRA2A expression correlates with improved PDAC survival and reduced invasion in PDAC cells C_LIO_LIUpregulated ADRA2A downregulates the MYC signaling pathway and promotes the classical/progenitor gene expression profile C_LIO_LIUpregulated ADRA2A induces a unique metabolic signature characterized by diminished amino acid and carnitine/acylcarnitine metabolism, resembling the classical/progenitor PDAC subtype C_LI

cancer biology↗

bioRxiv2023

LMO3 is a suppressor of the basal-like/squamous PDAC subtype and reduces disease aggressiveness of pancreatic cancer through glycerol 3-phosphate metabolism

Pancreatic ductal adenocarcinoma (PDAC) encompasses diverse molecular subtypes, including the classical/progenitor and basal-like/squamous subtypes, each exhibiting distinct characteristics, with the latter known for its aggressiveness. We employed an integrative approach combining transcriptomic and metabolomic analyses to pinpoint potential genes contributing to the basal-like/squamous subtype differentiation. Applying this approach to our NCI-UMD-German and a validation cohort, we identified LIM Domain Only 3 (LMO3), a transcription co-factor, as a candidate suppressor of the basal-like/squamous subtype. Reduced LMO3 expression was significantly associated with higher pathological grade, advanced disease stage, induction of the basal-like/squamous subtype, and decreased survival among PDAC patients. In vitro experiments demonstrated that LMO3 transgene expression inhibited PDAC cell proliferation and migration/invasion, concurrently downregulating the basal-like/squamous gene signature. Metabolomic analysis of patient tumors and PDAC cells revealed a metabolic program linked to elevated LMO3 expression and the classical/progenitor subtype, characterized by enhanced lipogenesis and suppressed amino acid metabolism. Notably, glycerol 3-phosphate (G3P) levels positively correlated with LMO3 expression and associated with improved patient survival. Furthermore, glycerol-3-phosphate dehydrogenase 1 (GPD1), a crucial enzyme in G3P synthesis, showed upregulation in LMO3-high and classical/progenitor PDAC, suggesting its potential role in mitigating disease aggressiveness. Collectively, our findings suggest that heightened LMO3 expression reduces transcriptomic and metabolomic characteristics indicative of basal-like/squamous tumors with decreased disease aggressiveness in PDAC patients. The observations describe LMO3 as a candidate for diagnostic and therapeutic targeting in PDAC. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=150 SRC="FIGDIR/small/564448v1_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@15ab2f1org.highwire.dtl.DTLVardef@199f209org.highwire.dtl.DTLVardef@1e1661corg.highwire.dtl.DTLVardef@f6eb7e_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LILMO3 is downregulated in basal-like/squamous PDAC while its expression is maintained in the classical/progenitor PDAC subtype C_LIO_LIUpregulated LMO3 expression correlates with improved PDAC survival and reduced proliferation and migration/invasion in PDAC cells C_LIO_LIUpregulated LMO3 suppresses basal-like/squamous differentiation and induces a unique metabolic signature characterized by elevated lipogenesis and diminished amino acid metabolism, resembling the classical/progenitor PDAC subtype C_LIO_LIEnhanced LMO3 expression associates with elevated glycerol 3-phosphate levels in PDAC, correlating with improved patient survival in PDAC C_LI

cancer biology↗

bioRxiv2023

ELAPOR1 induces the classical/progenitor subtype and contributes to reduced disease aggressiveness through metabolic reprogramming in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a heterogeneous disease with distinct molecular subtypes classified as classical/progenitor and basal-like/squamous. We hypothesized that integrative transcriptomic and metabolomic approaches can identify candidate genes whose inactivation contributes to the development of the aggressive basal-like/squamous subtype. Using our integrated approach, we identified endosome-lysosome associated apoptosis and autophagy regulator 1 (ELAPOR1/KIAA1324) as a candidate tumor suppressor in both our NCI-UMD-German cohort and validation cohorts. We found that decreased ELAPOR1 expression was significantly associated with high pathological grade, advanced disease stage, the basal-like/squamous subtype, and decreased survival in PDAC patients. In vitro experiments showed that ELAPOR1 transgene expression inhibited migration and invasion of PDAC cells. Metabolomic analysis of patient tumors and PDAC cells revealed a metabolic program associated with both upregulated ELAPOR1 and the classical/progenitor subtype, encompassing upregulated lipogenesis and downregulated amino acid metabolism. 1-methylnicotinamide, an oncometabolite derived from S-adenosylmethionine, was inversely associated with ELAPOR1 expression and promoted migration and invasion of PDAC cells in vitro. Taken together, our data suggest that enhanced ELAPOR1 expression promotes transcriptomic and metabolomic characteristics that are indicative of the classical/progenitor subtype, whereas its reduction associates with basal-like/squamous tumors with increased disease aggressiveness in PDAC patients. This positions ELAPOR1 as a promising candidate for diagnostic and therapeutic targeting in PDAC. Novelty and ImpactPancreatic ductal adenocarcinoma (PDAC) exhibits heterogeneous molecular subtypes: classical/progenitor and basal-like/squamous. Comprehensive transcriptome and metabolome analyses in the PDAC patient cohorts and PDAC cell lines revealed that elevated ELAPOR1 correlates with enhanced survival, reduced PDAC cell invasion, and a distinct metabolic signature resembling the classical/progenitor subtype. Additionally, 1-methylnicotinamide has been identified as an oncometabolite, showing an inverse correlation with ELAPOR1. These findings emphasize ELAPOR1s potential as a diagnostic and therapeutic target in PDAC. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/558894v1_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@f95c81org.highwire.dtl.DTLVardef@128334corg.highwire.dtl.DTLVardef@3fcb60org.highwire.dtl.DTLVardef@414011_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIELAPOR1 is downregulated in basal-like/squamous PDAC C_LIO_LIUpregulation of ELAPOR1 associates with improved PDAC survival and reduced migration and invasion in PDAC cells C_LIO_LIELAPOR1 expression induces a distinct metabolic signature as characterized by upregulation of lipogenesis and downregulation of amino acid metabolism, commonly observed in the classical/progenitor PDAC subtype C_LIO_LIThe oncometabolite, 1-methylnicotinamide (MNA) is decreased when ELAPOR1 is upregulated, and promotes the migration and invasion of PDAC cells C_LI

cancer biology↗