1
|
Xu J, Sabatino B, Yan J, Ermakova G, Doering KRS, Taubert S. The unfolded protein response of the endoplasmic reticulum protects Caenorhabditis elegans against DNA damage caused by stalled replication forks. G3 (Bethesda) 2024; 14:jkae017. [PMID: 38267027 PMCID: PMC10989892 DOI: 10.1093/g3journal/jkae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 12/21/2023] [Accepted: 01/14/2024] [Indexed: 01/26/2024]
Abstract
All animals must maintain genome and proteome integrity, especially when experiencing endogenous or exogenous stress. To cope, organisms have evolved sophisticated and conserved response systems: unfolded protein responses (UPRs) ensure proteostasis, while DNA damage responses (DDRs) maintain genome integrity. Emerging evidence suggests that UPRs and DDRs crosstalk, but this remains poorly understood. Here, we demonstrate that depletion of the DNA primases pri-1 or pri-2, which synthesize RNA primers at replication forks and whose inactivation causes DNA damage, activates the UPR of the endoplasmic reticulum (UPR-ER) in Caenorhabditis elegans, with especially strong activation in the germline. We observed activation of both the inositol-requiring-enzyme 1 (ire-1) and the protein kinase RNA-like endoplasmic reticulum kinase (pek-1) branches of the (UPR-ER). Interestingly, activation of the (UPR-ER) output gene heat shock protein 4 (hsp-4) was partially independent of its canonical activators, ire-1 and X-box binding protein (xbp-1), and instead required the third branch of the (UPR-ER), activating transcription factor 6 (atf-6), suggesting functional redundancy. We further found that primase depletion specifically induces the (UPR-ER), but not the distinct cytosolic or mitochondrial UPRs, suggesting that primase inactivation causes compartment-specific rather than global stress. Functionally, loss of ire-1 or pek-1 sensitizes animals to replication stress caused by hydroxyurea. Finally, transcriptome analysis of pri-1 embryos revealed several deregulated processes that could cause (UPR-ER) activation, including protein glycosylation, calcium signaling, and fatty acid desaturation. Together, our data show that the (UPR-ER), but not other UPRs, responds to replication fork stress and that the (UPR-ER) is required to alleviate this stress.
Collapse
Affiliation(s)
- Jiaming Xu
- Graduate Program in Cell & Developmental Biology, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Brendil Sabatino
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Department of Medical Genetics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Junran Yan
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Edwin S.H. Leong Centre for Healthy Aging, The University of British Columbia, 117-2194 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Medical Genetics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Glafira Ermakova
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Edwin S.H. Leong Centre for Healthy Aging, The University of British Columbia, 117-2194 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Medical Genetics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Kelsie R S Doering
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Edwin S.H. Leong Centre for Healthy Aging, The University of British Columbia, 117-2194 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Medical Genetics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Stefan Taubert
- Graduate Program in Cell & Developmental Biology, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Edwin S.H. Leong Centre for Healthy Aging, The University of British Columbia, 117-2194 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Medical Genetics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| |
Collapse
|
2
|
Richardson-Sanchez T, Chan ACK, Sabatino B, Lin H, Gaynor EC, Murphy MEP. Dissecting components of the Campylobacter jejuni fetMP-fetABCDEF gene cluster under iron limitation. Microbiol Spectr 2024; 12:e0314823. [PMID: 38096459 PMCID: PMC10783030 DOI: 10.1128/spectrum.03148-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/14/2023] [Indexed: 12/26/2023] Open
Abstract
IMPORTANCE Campylobacter jejuni is a bacterium that is prevalent in the ceca of farmed poultry such as chickens. Consumption of ill-prepared poultry is thus the most common route by which C. jejuni infects the human gut to cause a typically self-limiting but severe gastrointestinal illness that can be fatal to very young, old, or immunocompromised people. The lack of a vaccine and an increasing resistance to current antibiotics highlight a need to better understand the mechanisms that make C. jejuni a successful human pathogen. This study focused on the functional components of one such mechanism-a molecular system that helps C. jejuni thrive despite the restriction on growth-available iron by the human body, which typically defends against pathogens. In providing a deeper understanding of how this system functions, this study contributes toward the goal of reducing the enormous global socioeconomic burden caused by C. jejuni.
Collapse
Affiliation(s)
- Tomas Richardson-Sanchez
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Anson C. K. Chan
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Brendil Sabatino
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Helen Lin
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Erin C. Gaynor
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael E. P. Murphy
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
3
|
Richardson-Sanchez T, Chan ACK, Sabatino B, Lin H, Gaynor EC, Murphy MEP. Dissecting components of the Campylobacter jejuni fetMP-fetABCDEF gene cluster in iron scavenging. bioRxiv 2023:2023.07.05.547857. [PMID: 37461706 PMCID: PMC10350000 DOI: 10.1101/2023.07.05.547857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2023]
Abstract
Campylobacter jejuni is a leading cause of bacterial gastroenteritis worldwide. Acute infection can be antecedent to highly debilitating long-term sequelae. Expression of iron acquisition systems is vital for C. jejuni to survive the low iron availability within the human gut. The C. jejuni fetMP-fetABCDEF gene cluster is known to be upregulated during human infection and under iron limitation. While FetM and FetP have been functionally linked to iron transport in prior work, here we assess the contribution by each of the downstream genes ( fetABCDEF ) to C. jejuni growth during both iron-depleted and iron-replete conditions. Significant growth impairment was observed upon disruption of fetA , fetB, fetC , and fetD , suggesting a role in iron acquisition for each encoded protein. FetA expression was modulated by iron-availability but not dependent on the presence of FetB, FetC, FetD, FetE or FetF. Functions of the putative thioredoxins FetE and FetF were redundant in iron scavenging, requiring a double deletion (Δ fetEF ) to exhibit a growth defect. C. jejuni FetE was expressed and the structure solved to 1.50 Å, revealing structural similarity to thiol-disulfide oxidases. Functional characterization in biochemical assays showed that FetE reduced insulin at a slower rate than E. coli Trx and that together, FetEF promoted substrate oxidation in cell extracts, suggesting that FetE (and presumably FetF) are oxidoreductases that can mediate oxidation in vivo . This study advances our understanding of the contributions by the fetMP-fetABCDEF gene cluster to virulence at a genetic and functional level, providing foundational knowledge towards mitigating C. jejuni -related morbidity and mortality.
Collapse
|
4
|
Manchester AC, Hill S, Sabatino B, Armentano R, Carroll M, Kessler B, Miller M, Dogan B, McDonough SP, Simpson KW. Association between granulomatous colitis in French Bulldogs and invasive Escherichia coli and response to fluoroquinolone antimicrobials. J Vet Intern Med 2012. [PMID: 23206120 DOI: 10.1111/jvim.12020] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND French Bulldogs develop a form of granulomatous colitis (GC) with histopathological resemblance to GC of Boxer dogs (GCB). GCB is associated with mucosally invasive Escherichia coli whose eradication correlates with clinical remission. HYPOTHESIS/OBJECTIVES To characterize the clinical and histopathological features, presence or absence of invasive colonic bacteria, and response to fluoroquinolones in French Bulldogs with GC. ANIMALS A total of 6 French Bulldogs with a histological diagnosis of GC. METHODS Retrospective study of medical records. Bacterial colonization was evaluated using 16S rRNA probes for eubacteria and E. coli. Biopsy specimens from 3 dogs were cultured for bacteria. Clinical response to fluoroquinolone antimicrobials was determined. RESULTS All dogs were ≤1 year of age with hematochezia that was refractory to empirical therapy. Clinicopathologic and fecal analysis did not reveal abnormalities. Abdominal ultrasound revealed patchy thickening of the colon in 4/5 dogs and regional lymphadenopathy in 5/5. Colonoscopic abnormalities included irregularly thickened and ulcerated mucosa, hyperemia, and overt bleeding in 4/6 cases. Multifocal accumulations of PAS-positive macrophages and intramucosal E. coli were present in colonic biopsies of all 6 dogs. Administration of enrofloxacin (5/6) or marbofloxacin (1/6) at 4.4-10 mg/kg (median 10 mg/kg) PO q24h for 6-10 weeks was associated with clinical improvement within 5-14 days. All dogs remained in remission over a 3-30 month follow-up period. CONCLUSIONS Granulomatous colitis in young French Bulldogs is associated with the presence of invasive E. coli and closely parallels GCB. Treatment with fluoroquinolone antimicrobials can induce lasting clinical remission.
Collapse
Affiliation(s)
- A C Manchester
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Abstract
The urinary excretion of total protein, low-MW proteins, albumin, high-MW proteins, and intact IgG was measured in male Wistar rats between the ages of 5-52 weeks, and in rats with experimentally induced glomerular or tubular proteinuria. About 25% of aging rats spontaneously developed focal glomerulosclerosis and a mild glomerular proteinuria. By age 52 weeks, total protein excretion in rats with glomerulosclerosis exceeded that of unaffected rats by a factor of seven (39.5 vs 5.4 mg/24 hr x 100 g body wt), and albumin excretion was seven times higher than IgG excretion in affected rats (21.2 vs 2.9 mg/24 hr x 100 g body wt). Rats with chromate toxicity exhibited a reversible tubular proteinuria, with low-molecular weight protein excretion reaching 16.8 mg/24 hr x 100 g body wt (75% of total protein excretion) at the time of peak toxicity. IgG excretion remained less than 0.6 mg/24 hr x 100 g body wt. Aminonucleoside induced a massive but reversible glomerular proteinuria (204 mg/24 hr x 100 g body wt), with IgG excretion reaching 11.4 mg/24 hr x 100 g body wt (6% of total protein excretion) at the time of peak toxicity. Biochemical and immunochemical studies showed that, while some intact IgG is present in normal rat urine, most IgG immunoreactivity is derived from low-molecular weight catabolic fragments of IgG which interfere with the immunoassay of intact urinary IgG. One of these fragments, probably Fc fragment, may be involved in the pathogenesis of focal segmental glomerulosclerosis.
Collapse
Affiliation(s)
- B Sabatino
- Department of Experimental Pathology, Roswell Park Cancer Institute, Buffalo, New York 14203, USA
| | | |
Collapse
|