1
|
Huang X, Sun T, Wang J, Hong X, Chen H, Yan T, Zhou C, Sun D, Yang C, Yu T, Su W, Du W, Xiong H. Metformin Reprograms Tryptophan Metabolism to Stimulate CD8+ T-cell Function in Colorectal Cancer. Cancer Res 2023; 83:2358-2371. [PMID: 37195082 DOI: 10.1158/0008-5472.can-22-3042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 04/02/2023] [Accepted: 05/12/2023] [Indexed: 05/18/2023]
Abstract
Colorectal carcinogenesis coincides with immune cell dysfunction. Metformin has been reported to play a role in stimulating antitumor immunity, suggesting it could be used to overcome immunosuppression in colorectal cancer. Herein, using single-cell RNA sequencing (scRNA-seq), we showed that metformin remodels the immune landscape of colorectal cancer. In particular, metformin treatment expanded the proportion of CD8+ T cells and potentiated their function. Analysis of the metabolic activities of cells in the colorectal cancer tumor microenvironment (TME) at a single-cell resolution demonstrated that metformin reprogrammed tryptophan metabolism, which was reduced in colorectal cancer cells and increased in CD8+ T cells. Untreated colorectal cancer cells outcompeted CD8+ T cells for tryptophan, leading to impaired CD8+ T-cell function. Metformin in turn reduced tryptophan uptake by colorectal cancer cells, thereby restoring tryptophan availability for CD8+ T cells and increasing their cytotoxicity. Metformin inhibited tryptophan uptake in colorectal cancer cells by downregulating MYC, which led to a reduction in the tryptophan transporter SLC7A5. This work highlights metformin as an essential regulator of T-cell antitumor immunity by reprogramming tryptophan metabolism, suggesting it could be a potential immunotherapeutic strategy for treating colorectal cancer. SIGNIFICANCE Analysis of the impact of metformin on the colorectal cancer immunometabolic landscape at a single-cell resolution shows that metformin alters cancer cell tryptophan metabolism to stimulate CD8+ T-cell antitumor activity.
Collapse
Affiliation(s)
- Xiaowen Huang
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Tiantian Sun
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Jilin Wang
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Xialu Hong
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Huimin Chen
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Tingting Yan
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Chengbei Zhou
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Danfeng Sun
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Chen Yang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - TaChung Yu
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Wenyu Su
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Wan Du
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| | - Hua Xiong
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China
| |
Collapse
|
2
|
Ceder MM, Lekholm E, Hellsten SV, Perland E, Fredriksson R. The Neuronal and Peripheral Expressed Membrane-Bound UNC93A Respond to Nutrient Availability in Mice. Front Mol Neurosci 2017; 10:351. [PMID: 29163028 PMCID: PMC5671512 DOI: 10.3389/fnmol.2017.00351] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 10/13/2017] [Indexed: 12/31/2022] Open
Abstract
Many transporters such as the solute carriers belonging to the Major facilitator superfamily Pfam clan are orphans in that their tissue and cellular localization as well as substrate profile and function are still unknown. Here we have characterized the putative solute carrier UNC93A. We aimed to investigate the expression profile on both protein and mRNA level of UNC93A in mouse since it has not been clarified. UNC93A staining was found in cortex, hippocampus and cerebellum. It was found to be expressed in many neurons, but not all, with staining located in close proximity to the plasma membrane. Furthermore, we aimed to extend the starvation data available for Unc93a in hypothalamic cell cultures from mouse. We investigated the Unc93a alterations with focus on amino acid deprivation in embryonic cortex cells from mice as well as 24 h starvation in adult male mice and compared it to recently studied putative and known solute carriers. Unc93a expression was found both in the brain and peripheral organs, in low to moderate levels in the adult mice and was affected by amino acid deprivation in embryonic cortex cultures and starvation in in vivo samples. In conclusion, the membrane-bound UNC93A is expressed in both the brain and peripheral tissues and responds to nutrient availability in mice.
Collapse
Affiliation(s)
- Mikaela M Ceder
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Emilia Lekholm
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Sofie V Hellsten
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Emelie Perland
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Robert Fredriksson
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| |
Collapse
|
3
|
Piert M, Shao X, Raffel D, Davenport MS, Montgomery J, Kunju LP, Hockley BG, Siddiqui J, Scott PJH, Chinnaiyan AM, Rajendiran T. Preclinical Evaluation of 11C-Sarcosine as a Substrate of Proton-Coupled Amino Acid Transporters and First Human Application in Prostate Cancer. J Nucl Med 2017; 58:1216-1223. [PMID: 28302759 DOI: 10.2967/jnumed.116.173179] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/14/2017] [Indexed: 12/14/2022] Open
Abstract
Sarcosine is a known substrate of proton-coupled amino acid transporters (PATs), which are overexpressed in selected tissues and solid tumors. Sarcosine, an N-methyl derivative of the amino acid glycine and a metabolic product of choline, plays an important role for prostate cancer aggressiveness and progression. Methods:11C-radiolabeled sarcosine was tested as a new PET imaging probe in comparison with 11C-choline in 2 prostate cancer tumor xenograft models (DU-145 and PC-3). We characterized 11C-sarcosine transport in PC-3 and LNCaP tumor cells and performed 11C-sarcosine PET with CT in the first human subject with localized Gleason 4 + 3 prostate cancer. Target metabolite analyses of sarcosine and its natural precursors, glycine and choline, were performed from independent human prostate tissues. Results: In vitro assays indicated blockage of 11C-sarcosine uptake into PC-3 and LNCaP tumor cells by excess unlabeled (cold) sarcosine. 5-hydroxy-l-tryptophan, but not 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid, competitively inhibited 11C-sarcosine tumor cell uptake, confirming PAT-mediated transport. In vivo tumor-to-background ratios (TBRs) obtained from 11C-sarcosine PET were significantly elevated compared with 11C-choline in DU-145 (TBR: 1.92 ± 0.11 for 11C-sarcosine vs. 1.41 ± 0.13 for 11C-choline [n = 10; P < 0.002]) and PC-3 tumors (TBR: 1.89 ± 0.2 for 11C-sarcosine vs. 1.34 ± 0.16 for 11C-choline [n = 7; P < 0.002]). 11C-sarcosine produced high-contrast images in 1 case of localized clinically significant prostate cancer. Target metabolite analyses revealed significant stepwise increases of sarcosine, glycine, and choline tissue levels from benign prostate tissue to localized prostate cancer and subsequently metastatic disease. 11C-sarcosine showed a favorable radiation dosimetry with an effective dose estimate of 0.0045 mSv/MBq, resulting in 2.68 mSv for a human subject (600-MBq dose). Conclusion:11C-sarcosine is a novel radiotracer for PATs and shows initial utility for prostate cancer imaging, with potential benefit over commonly used 11C-choline.
Collapse
Affiliation(s)
- Morand Piert
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Xia Shao
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - David Raffel
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | | | | | | | - Brian G Hockley
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Javed Siddiqui
- Pathology Department, University of Michigan, Ann Arbor, Michigan; and.,Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, Michigan
| | - Peter J H Scott
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Arul M Chinnaiyan
- Pathology Department, University of Michigan, Ann Arbor, Michigan; and.,Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, Michigan
| | - Thekkelnaycke Rajendiran
- Pathology Department, University of Michigan, Ann Arbor, Michigan; and.,Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, Michigan
| |
Collapse
|
4
|
Hellsten SV, Eriksson MM, Lekholm E, Arapi V, Perland E, Fredriksson R. The gene expression of the neuronal protein, SLC38A9, changes in mouse brain after in vivo starvation and high-fat diet. PLoS One 2017; 12:e0172917. [PMID: 28235079 PMCID: PMC5325605 DOI: 10.1371/journal.pone.0172917] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/03/2017] [Indexed: 11/18/2022] Open
Abstract
SLC38A9 is characterized as a lysosomal component of the amino acid sensing Ragulator-RAG GTPase complex, controlling the mechanistic target of rapamycin complex 1 (mTORC1). Here, immunohistochemistry was used to map SLC38A9 in mouse brain and staining was detected throughout the brain, in cortex, hypothalamus, thalamus, hippocampus, brainstem and cerebellum. More specifically, immunostaining was found in areas known to be involved in amino acid sensing and signaling pathways e.g. piriform cortex and hypothalamus. SLC38A9 immunoreactivity co-localized with both GABAergic and glutamatergic neurons, but not with astrocytes. SLC38A9 play a key role in the mTORC1 pathway, and therefore we performed in vivo starvation and high-fat diet studies, to measure gene expression alterations in specific brain tissues and in larger brain regions. Following starvation, Slc38a9 was upregulated in brainstem and cortex, and in anterior parts of the brain (Bregma 3.2 to -2.1mm). After high-fat diet, Slc38a9 was specifically upregulated in hypothalamus, while overall downregulation was noticed throughout the brain (Bregma 3.2 to -8.6mm).
Collapse
Affiliation(s)
- Sofie V. Hellsten
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
- * E-mail:
| | - Mikaela M. Eriksson
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
| | - Emilia Lekholm
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
| | - Vasiliki Arapi
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
| | - Emelie Perland
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
| | - Robert Fredriksson
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
| |
Collapse
|
5
|
Lekholm E, Perland E, Eriksson MM, Hellsten SV, Lindberg FA, Rostami J, Fredriksson R. Putative Membrane-Bound Transporters MFSD14A and MFSD14B Are Neuronal and Affected by Nutrient Availability. Front Mol Neurosci 2017; 10:11. [PMID: 28179877 PMCID: PMC5263138 DOI: 10.3389/fnmol.2017.00011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 01/09/2017] [Indexed: 11/13/2022] Open
Abstract
Characterization of orphan transporters is of importance due to their involvement in cellular homeostasis but also in pharmacokinetics and pharmacodynamics. The tissue and cellular localization, as well as function, is still unknown for many of the solute carriers belonging to the major facilitator superfamily (MFS) Pfam clan. Here, we have characterized two putative novel transporters MFSD14A (HIAT1) and MFSD14B (HIATL1) in the mouse central nervous system and found protein staining throughout the adult mouse brain. Both transporters localized to neurons and MFSD14A co-localized with the Golgi marker Giantin in primary embryonic cortex cultures, while MFSD14B staining co-localized with an endoplasmic retention marker, KDEL. Based on phylogenetic clustering analyses, we predict both to have organic substrate profiles, and possible involvement in energy homeostasis. Therefore, we monitored gene regulation changes in mouse embryonic primary cultures after amino acid starvations and found both transporters to be upregulated after 3 h of starvation. Interestingly, in mice subjected to 24 h of food starvation, both transporters were downregulated in the hypothalamus, while Mfsd14a was also downregulated in the brainstem. In addition, in mice fed a high fat diet (HFD), upregulation of both transporters was seen in the striatum. Both MFSD14A and MFSD14B were intracellular neuronal membrane-bound proteins, expressed in the Golgi and Endoplasmic reticulum, affected by both starvation and HFD to varying degree in the mouse brain.
Collapse
Affiliation(s)
- Emilia Lekholm
- Department of Neuroscience, Functional Pharmacology, Uppsala UniversityUppsala, Sweden; Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala UniversityUppsala, Sweden
| | - Emelie Perland
- Department of Neuroscience, Functional Pharmacology, Uppsala UniversityUppsala, Sweden; Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala UniversityUppsala, Sweden
| | - Mikaela M Eriksson
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University Uppsala, Sweden
| | - Sofie V Hellsten
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University Uppsala, Sweden
| | - Frida A Lindberg
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University Uppsala, Sweden
| | - Jinar Rostami
- Department of Neuroscience, Functional Pharmacology, Uppsala University Uppsala, Sweden
| | - Robert Fredriksson
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University Uppsala, Sweden
| |
Collapse
|
6
|
Lin WY, Williams CR, Yan C, Parrish JZ. Functions of the SLC36 transporter Pathetic in growth control. Fly (Austin) 2016; 9:99-106. [PMID: 26735916 DOI: 10.1080/19336934.2015.1129089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Neurons exhibit extreme diversity in size, but whether large neurons have specialized mechanisms to support their growth is largely unknown. Recently, we identified the SLC36 transporter Pathetic (Path) as a factor required for extreme dendrite growth in neurons. Path is broadly expressed, but only neurons with large dendrite arbors or small neurons that are forced to grow large require path for their growth. To gain insight into the basis of growth control by path, we generated additional alleles of path and further examined the apparent specificity of growth defects in path mutants. Here, we confirm our prior finding that loss of path function imposes an upper limit on neuron growth, and additionally report that path likely limits overall neurite length rather than dendrite length alone. Using a GFP knock-in allele of path, we identify additional tissues where path likely functions in nutrient sensing and possibly growth control. Finally, we demonstrate that path regulates translational capacity in a cell type that does not normally require path for growth, suggesting that path may confer robustness on growth programs by buffering translational output. Altogether, these studies suggest that Path is a nutrient sensor with widespread function in Drosophila.
Collapse
Affiliation(s)
- Wen-Yang Lin
- a Department of Biology ; University of Washington ; Seattle , WA USA
| | - Claire R Williams
- a Department of Biology ; University of Washington ; Seattle , WA USA
| | - Connie Yan
- a Department of Biology ; University of Washington ; Seattle , WA USA
| | - Jay Z Parrish
- a Department of Biology ; University of Washington ; Seattle , WA USA
| |
Collapse
|
7
|
Roshanbin S, Lindberg FA, Lekholm E, Eriksson MM, Perland E, Åhlund J, Raine A, Fredriksson R. Histological characterization of orphan transporter MCT14 (SLC16A14) shows abundant expression in mouse CNS and kidney. BMC Neurosci 2016; 17:43. [PMID: 27364523 PMCID: PMC4929735 DOI: 10.1186/s12868-016-0274-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 06/15/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND MCT14 (SLC16A14) is an orphan member of the monocarboxylate transporter (MCT) family, also known as the SLC16 family of secondary active transmembrane transporters. Available expression data for this transporter is limited, and in this paper we aim to characterize MCT14 with respect to tissue distribution and cellular localization in mouse brain. RESULTS Using qPCR, we found that Slc16a14 mRNA was highly abundant in mouse kidney and moderately in central nervous system, testis, uterus and liver. Using immunohistochemistry and in situ hybridization, we determined that MCT14 was highly expressed in excitatory and inhibitory neurons as well as epithelial cells in the mouse brain. The expression was exclusively localized to the soma of neurons. Furthermore, we showed with our phylogenetic analysis that MCT14 most closely relate to the aromatic amino acid- and thyroid-hormone transporters MCT8 (SLC16A2) and MCT10 (SLC16A10), in addition to the carnitine transporter MCT9 (SLC16A9). CONCLUSIONS We provide here the first histological mapping of MCT14 in the brain and our data are consistent with the hypothesis that MCT14 is a neuronal aromatic-amino-acid transporter.
Collapse
Affiliation(s)
- Sahar Roshanbin
- Department of Neuroscience, Functional Pharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Frida A Lindberg
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Emilia Lekholm
- Department of Neuroscience, Functional Pharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Mikaela M Eriksson
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Emelie Perland
- Department of Neuroscience, Functional Pharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Johan Åhlund
- Department of Neuroscience, Functional Pharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Amanda Raine
- Department of Neuroscience, Functional Pharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Robert Fredriksson
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, 75124, Uppsala, Sweden.
| |
Collapse
|
8
|
Lin WY, Williams C, Yan C, Koledachkina T, Luedke K, Dalton J, Bloomsburg S, Morrison N, Duncan KE, Kim CC, Parrish JZ. The SLC36 transporter Pathetic is required for extreme dendrite growth in Drosophila sensory neurons. Genes Dev 2015; 29:1120-35. [PMID: 26063572 PMCID: PMC4470281 DOI: 10.1101/gad.259119.115] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lin et al. identified a mutant that selectively affects dendrite growth in neurons with large dendrite arbors without affecting dendrite growth in neurons with small dendrite arbors or the animal overall. This mutant disrupts a putative amino acid transporter, Pathetic (Path), that localizes to the cell surface and endolysosomal compartments in neurons. Dendrites exhibit enormous diversity in form and can differ in size by several orders of magnitude even in a single animal. However, whether neurons with large dendrite arbors have specialized mechanisms to support their growth demands is unknown. To address this question, we conducted a genetic screen for mutations that differentially affected growth in neurons with different-sized dendrite arbors. From this screen, we identified a mutant that selectively affects dendrite growth in neurons with large dendrite arbors without affecting dendrite growth in neurons with small dendrite arbors or the animal overall. This mutant disrupts a putative amino acid transporter, Pathetic (Path), that localizes to the cell surface and endolysosomal compartments in neurons. Although Path is broadly expressed in neurons and nonneuronal cells, mutation of path impinges on nutrient responses and protein homeostasis specifically in neurons with large dendrite arbors but not in other cells. Altogether, our results demonstrate that specialized molecular mechanisms exist to support growth demands in neurons with large dendrite arbors and define Path as a founding member of this growth program.
Collapse
Affiliation(s)
- Wen-Yang Lin
- Department of Biology, University of Washington, Seattle, Washington 98195, USA
| | - Claire Williams
- Department of Biology, University of Washington, Seattle, Washington 98195, USA
| | - Connie Yan
- Department of Biology, University of Washington, Seattle, Washington 98195, USA
| | - Tatyana Koledachkina
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg D-20251, Germany
| | - Kory Luedke
- Department of Biology, University of Washington, Seattle, Washington 98195, USA
| | - Jesse Dalton
- Department of Biology, University of Washington, Seattle, Washington 98195, USA
| | - Sam Bloomsburg
- Department of Biology, University of Washington, Seattle, Washington 98195, USA
| | - Nicole Morrison
- Department of Biology, University of Washington, Seattle, Washington 98195, USA
| | - Kent E Duncan
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg D-20251, Germany
| | - Charles C Kim
- Division of Experimental Medicine, Department of Medicine, University of California at San Francisco, San Francisco, California 94110, USA
| | - Jay Z Parrish
- Department of Biology, University of Washington, Seattle, Washington 98195, USA;
| |
Collapse
|