Project description:Distinct retrograde signaling pathways have been identified for several cellular organelles. These pathways are important to maintain the function of these organelles in response to organelle-specific stress. Using Caenorhabditis elegans, we show for the first time that such a retrograde signaling also exists for peroxisomes. Analysis of the C. elegans transcriptome revealed that peroxisomal import stress caused by the knock-down of the peroxisomal matrix protein import receptor prx-5/PEX5 induces the compensatory up-regulation of genes involved in defense response and lipid metabolic processes, especially peroxisomal beta oxidation. We, therefore, propose that the peroxisomal retrograde signaling participates in the maintenance of peroxisomal function in response to peroxisomal import stress.
Project description:While retrograde signalling pathways have been identified for several organelles, the existence of such a pathway for peroxisomes remains elusive. We identified a peroxisomal retrograde signalling (PRS) in C. elegans, which is activated in response to peroxisomal import stress. We analyzed the PRS using a proteomic approach.
Project description:Helf MJ, Fox BW, Artyukhin AB, Zhang YK, Schroeder FC (2021) Comparative metabolomics with Metaboseek reveals functions of peroxisomal alpha-oxidation in C. elegans
Project description:Retrograde signaling from axon to soma activates intrinsic regeneration mechanisms in lesioned peripheral sensory neurons; however, the links between axonal injury signaling and the cell body response are not well understood. Here, we used phosphoproteomics and microarrays to implicate ~900 phosphoproteins in retrograde injury signaling in rat sciatic nerve axons in vivo and ~4500 transcripts in the in vivo response to injury in the dorsal root ganglia. Computational analyses of these data sets identified ~400 redundant axonal signaling networks connected to 39 transcription factors implicated in the sensory neuron response to axonal injury. Experimental perturbation of individual overrepresented signaling hub proteins, including Abl, AKT, p38, and protein kinase C, affected neurite outgrowth in sensory neurons. Paradoxically, however, combined perturbation of Abl together with other hub proteins had a reduced effect relative to perturbation of individual proteins. Our data indicate that nerve injury responses are controlled by multiple regulatory components, and suggest that network redundancies provide robustness to the injury response Microarrays were run on mRNA extracted from adult rat L4 and L5 DRGs cells after 1,3,8,12,16,18,24, and 28 hours after a sciatic nerve (proximal and distal) lesion.
Project description:The mitochondrial and nuclear genomes contribute to mitochondrial function, and when mitochondrial function is compromised, mitochondrial retrograde signaling alters nuclear gene expression. We performed gene expression profiling of engineered cells that had mitochondria containing a disease-associated mutation that causes mitochondrial dysfunction. By generating networks of transcription factors that targeted these genes, the authors revealed putative mitochondrial retrograde signaling pathways. One such pathway involved retinoic acid receptor alpha (RXRA), the mRNA for which was reduced in the mutant cells. Network analysis and experiments in cells suggested that mitochondrial dysfunction caused by the mutation initiated a positive feedback loop that aggravated mitochondrial dysfunction: Reduced RXRA abundance further compromised expression of genes encoding products involved in mitochondrial function and translation. This gene-transcription factor mapping-network approach may reveal targets for therapeutic intervention of diseases associated with mitochondrial dysfunction. To investigate retrograde signaling pathways induced by the mitochondrial dysfunction caused by the mt3243 mutation, we generated the three types of cybrid cells using a mitochondria-mediated transformation method. Cells lacking mtDNA (rho0) were fused with mtDNAs with the mt3243 mutation isolated from platelets of a diabetic patient with sensorineural hearing loss. We then isolated three types of cybrid cells: W cells had wild-type mtDNA (3243A homoplasmy), H cells had both the mutant and wild-type mtDNA (3243A/G heteroplasmy) with 70% of the mtDNA containing 3243G, and M cells with only mutant mtDNA (3243G homoplasmy). Gene expression profiles of cybrid cells were generated using Illumina HumanHT-12-v3-BeadChip (Illumina, San Diego, CA), which includes 49,896 probes corresponding to 25,202 annotated genes. According to the Illumina protocols, three biological triplicates of each type of cybrid cells were analyzed. Total RNA (500ng) was isolated from cybrid cells using RNeasy Mini Kit (Qiagen, GmbH, Germany). RNA integrity number (RIN) was in the range of RIN = 9.2 and 10 when measured with an Agilent 2100 Bioanalyzer. RNA was reversely transcribed and amplified using IlluminaTotalPrep RNA amplification kit (Ambion, Austin, TX). In vitro transcription was then carried out to prepare cRNA. The cRNAs were hybridized to the array and then labeled with Cy3-streptavidin (Amersham Bioscience, Little Chalfont, UK). The fluorescent signal on the array was measured with a BeadStation 500 System (Illumina, San Diego, CA).
Project description:Retrograde signaling from axon to soma activates intrinsic regeneration mechanisms in lesioned peripheral sensory neurons; however, the links between axonal injury signaling and the cell body response are not well understood. Here, we used phosphoproteomics and microarrays to implicate ~900 phosphoproteins in retrograde injury signaling in rat sciatic nerve axons in vivo and ~4500 transcripts in the in vivo response to injury in the dorsal root ganglia. Computational analyses of these data sets identified ~400 redundant axonal signaling networks connected to 39 transcription factors implicated in the sensory neuron response to axonal injury. Experimental perturbation of individual overrepresented signaling hub proteins, including Abl, AKT, p38, and protein kinase C, affected neurite outgrowth in sensory neurons. Paradoxically, however, combined perturbation of Abl together with other hub proteins had a reduced effect relative to perturbation of individual proteins. Our data indicate that nerve injury responses are controlled by multiple regulatory components, and suggest that network redundancies provide robustness to the injury response
Project description:The mitochondrial and nuclear genomes contribute to mitochondrial function, and when mitochondrial function is compromised, mitochondrial retrograde signaling alters nuclear gene expression. We performed gene expression profiling of engineered cells that had mitochondria containing a disease-associated mutation that causes mitochondrial dysfunction. By generating networks of transcription factors that targeted these genes, the authors revealed putative mitochondrial retrograde signaling pathways. One such pathway involved retinoic acid receptor alpha (RXRA), the mRNA for which was reduced in the mutant cells. Network analysis and experiments in cells suggested that mitochondrial dysfunction caused by the mutation initiated a positive feedback loop that aggravated mitochondrial dysfunction: Reduced RXRA abundance further compromised expression of genes encoding products involved in mitochondrial function and translation. This gene-transcription factor mapping-network approach may reveal targets for therapeutic intervention of diseases associated with mitochondrial dysfunction.
Project description:Helf MJ, Fox BW, Artyukhin AB, Zhang YK, Schroeder FC (2021) Comparative metabolomics with Metaboseek reveals functions of peroxisomal alpha-oxidation in C. elegans
Project description:Chloroplast-nuclear retrograde signaling is viewed as a mechanism for inter-organelle communication. Here we show the SAL1-PAP (3′-phosphoadenosine 5′- phosphate) retrograde pathway functions more broadly in guard cells, interacting with abscisic acid (ABA) signaling at least in part via exoribonucleases. Unexpectedly, PAP bypasses the canonical signaling components ABA Insensitive 1 (ABI1) and Open Stomata 1 (OST1) by priming an alternative pathway that restores ABA-responsive gene expression, ROS bursts, ion channel function and stomatal closure in ost1-2. This alternative pathway up-regulates lowly expressed Calcium Dependent Protein Kinases (CDPKs) which have the capacity to activate the key slow anion channel SLAC1 in response to ABA-mediated and ost1-2 independent calcium release. The role of PAP in priming an alternative pathway to bypass components previously considered essential for stomatal closure demonstrates how a chloroplast signal can have broader roles as a secondary messenger to directly intersect with and tune hormone signaling.