scholarly journals Erythrocytes as Biomarkers of Virus and Bacteria in View of Metal Ion Homeostasis

2021 ◽  
Author(s):  
Erland Johansson ◽  
Anders B. Falk

The erythrocyte contributes to the immune system in several ways. It sequesters interferons, interleukins or chemokines and by binding nucleic acid. It binds virus and bacteria and may deliver bacteria to macrophages for phagocytosis. It may also kill bacteria directly with oxygen. For proper function of the erythrocyte, homeostasis of reactive oxygen species, selenium, metal ions and trace elements is important. Erythrocytes display morphological and metabolic changes in diseases like sepsis, and in several genetic diseases. Patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), giving rise to the coronavirus disease 2019 (Covid-19), show many erythrocyte changes as compared to healthy controls. The erythrocyte responds to hemolysins by purinergic signaling leading to hemolysis or phosphatidylserine exposure on the plasma membrane. Phosphatidylserine marks erythrocytes for clearance by spleen macrophages. Regulated erythrocyte cell death, also called eryptosis, can be induced by oxidative stress, pathogen infection, and certain diseases like sepsis. Erythrocytes may, in the future, contribute more to diagnosis based on research and diagnostic technological development.

2006 ◽  
Vol 188 (14) ◽  
pp. 5033-5044 ◽  
Author(s):  
Elizabeth Rolerson ◽  
Adam Swick ◽  
Lindsay Newlon ◽  
Cameron Palmer ◽  
Yong Pan ◽  
...  

ABSTRACT Metal ion availability in the human oral cavity plays a putative role in Streptococcus mutans virulence gene expression and in appropriate formation of the plaque biofilm. In this report, we present evidence that supports such a role for the DtxR-like SloR metalloregulator (called Dlg in our previous publications) in this oral pathogen. Specifically, the results of gel mobility shift assays revealed the sloABC, sloR, comDE, ropA, sod, and spaP promoters as targets of SloR binding. We confirmed differential expression of these genes in a GMS584 SloR-deficient mutant versus the UA159 wild-type progenitor by real-time semiquantitative reverse transcriptase PCR experiments. The results of additional expression studies support a role for SloR in S. mutans control of glucosyltransferases, glucan binding proteins, and genes relevant to antibiotic resistance. Phenotypic analysis of GMS584 revealed that it forms aberrant biofilms on an abiotic surface, is compromised for genetic competence, and demonstrates heightened incorporation of iron and manganese as well as resistance to oxidative stress compared to the wild type. Taken together, these findings support a role for SloR in S. mutans adherence, biofilm formation, genetic competence, metal ion homeostasis, oxidative stress tolerance, and antibiotic gene regulation, all of which contribute to S. mutans-induced disease.


2020 ◽  
Vol 227 (4) ◽  
pp. 1174-1188 ◽  
Author(s):  
Robin Nostadt ◽  
Magdalena Hilbert ◽  
Shadab Nizam ◽  
Hanna Rovenich ◽  
Stephan Wawra ◽  
...  

2018 ◽  
Vol 28 (18) ◽  
pp. 1669-1703 ◽  
Author(s):  
Carla Garza-Lombó ◽  
Yanahi Posadas ◽  
Liliana Quintanar ◽  
María E. Gonsebatt ◽  
Rodrigo Franco

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 289
Author(s):  
Jie Li ◽  
Yanzhuang Wang

The Golgi apparatus is a membrane organelle located in the center of the protein processing and trafficking pathway. It consists of sub-compartments with distinct biochemical compositions and functions. Main functions of the Golgi, including membrane trafficking, protein glycosylation, and sorting, require a well-maintained stable microenvironment in the sub-compartments of the Golgi, along with metal ion homeostasis. Metal ions, such as Ca2+, Mn2+, Zn2+, and Cu2+, are important cofactors of many Golgi resident glycosylation enzymes. The homeostasis of metal ions in the secretory pathway, which is required for proper function and stress response of the Golgi, is tightly regulated and maintained by transporters. Mutations in the transporters cause human diseases. Here we provide a review specifically focusing on the transporters that maintain Golgi metal ion homeostasis under physiological conditions and their alterations in diseases.


2019 ◽  
Vol 476 (4) ◽  
pp. 699-703
Author(s):  
Nicholas S. Jakubovics

Abstract The ability of opportunistic pathogens such as Group A Streptococcus (GAS) to transition between mucosal colonisation and invasive disease requires complex systems for adapting to markedly different host environments. The battle to acquire essential trace metals such as manganese and iron from the host is central to pathogenesis. Using a molecular genetic approach, Turner et al. [Biochem. J. (2019) 476, 595–611] show that it is not just individual metal concentrations that are important, but the ratio of iron to manganese within cells. Increasing this ratio by knocking out pmtA, encoding the Fe(II) exporter PmtA, or by disrupting mtsA, encoding an MtsABC Mn(II)-import system component, led to reductions in superoxide dismutase (SodA) activity and increased sensitivity to oxidative stress. The authors show that SodA is at least 4-fold more active with Mn bound than with Fe and speculate that high intracellular Fe:Mn ratios reduce superoxide dismutase activity through the mismetalation of SodA. Challenging wild-type GAS with 1 mM H2O2 led to a decrease in Fe:Mn ratio and a 3-fold increase in SodA activity, indicating that modulation of the balance between intracellular Fe and Mn may play an important role in adaptation to oxidative stress. This work unravels some of the key mechanisms for maintaining appropriate Mn and Fe concentrations within bacterial cells and underscores the need for future studies that take an holistic view to metal ion homeostasis in bacteria. Strategies aimed at interfering with the balance of intracellular metal ions represent a promising approach for the control of invasive microbial infections.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
A. Sukumaran ◽  
S. Pladwig ◽  
J. Geddes-McAlister

Abstract Background Microbial organisms encounter a variety of environmental conditions, including changes to metal ion availability. Metal ions play an important role in many biological processes for growth and survival. As such, microbes alter their cellular protein levels and secretion patterns in adaptation to a changing environment. This study focuses on Klebsiella pneumoniae, an opportunistic bacterium responsible for nosocomial infections. By using K. pneumoniae, we aim to determine how a nutrient-limited environment (e.g., zinc depletion) modulates the cellular proteome and secretome of the bacterium. By testing virulence in vitro, we provide novel insight into bacterial responses to limited environments in the presence of the host. Results Analysis of intra- and extracellular changes identified 2380 proteins from the total cellular proteome (cell pellet) and 246 secreted proteins (supernatant). Specifically, HutC, a repressor of the histidine utilization operon, showed significantly increased abundance under zinc-replete conditions, which coincided with an expected reduction in expression of genes within the hut operon from our validating qRT-PCR analysis. Additionally, we characterized a putative cation transport regulator, ChaB that showed significantly higher abundance under zinc-replete vs. -limited conditions, suggesting a role in metal ion homeostasis. Phenotypic analysis of a chaB deletion strain demonstrated a reduction in capsule production, zinc-dependent growth and ion utilization, and reduced virulence when compared to the wild-type strain. Conclusions This is first study to comprehensively profile the impact of zinc availability on the proteome and secretome of K. pneumoniae and uncover a novel connection between zinc transport and capsule production in the bacterial system.


2003 ◽  
Vol 18 (3) ◽  
pp. 162-169 ◽  
Author(s):  
S.E. Theocharis ◽  
A.P. Margeli ◽  
A. Koutselinis

The metallothionein (MT) family is a class of low molecular weight, intracellular and cysteine-rich proteins presenting high affinity for metal ions. Although the members of this family were discovered nearly 40 years ago, their functional significance remains obscure. Four major MT isoforms, MT-1, MT-2, MT-3 and MT-4, have been identified in mammals. MTs are involved in many pathophysiological processes such as metal ion homeostasis and detoxification, protection against oxidative damage, cell proliferation and apoptosis, chemoresistance and radiotherapy resistance. MT isoforms have been shown to be involved in several aspects of the carcinogenic process, cancer development and progression. MT expression has been implicated as a transient response to any form of stress or injury providing cytoprotective action. Although MT participates in the carcinogenic process, its use as a potential marker of tumor differentiation or cell proliferation, or as a predictor of poor prognosis remains unclear. In the present review the involvement of MT in defense mechanisms to toxicity and in carcinogenicity is discussed.


2018 ◽  
Vol 314 (3) ◽  
pp. F423-F429 ◽  
Author(s):  
Danielle L. Kirkman ◽  
Bryce J. Muth ◽  
Meghan G. Ramick ◽  
Raymond R. Townsend ◽  
David G. Edwards

Cardiovascular disease is the leading cause of mortality in chronic kidney disease (CKD). Mitochondrial dysfunction secondary to CKD is a potential source of oxidative stress that may impair vascular function. This study sought to determine if mitochondria-derived reactive oxygen species contribute to microvascular dysfunction in stage 3–5 CKD. Cutaneous vasodilation in response to local heating was assessed in 20 CKD patients [60 ± 13 yr; estimated glomerular filtration rate (eGFR) 46 ± 13 ml·kg−1·1.73 m−2] and 11 matched healthy participants (58 ± 2 yr; eGFR >90 ml·kg−1·1.73 m−2). Participants were instrumented with two microdialysis fibers for the delivery of 1) Ringer solution, and 2) the mitochondria- specific superoxide scavenger MitoTempo. Skin blood flow was measured via laser Doppler flowmetry during standardized local heating (42°C). Cutaneous vascular conductance (CVC) was calculated as a percentage of the maximum conductance achieved with sodium nitroprusside infusion at 43°C. Urinary isofuran/F2-isoprostane ratios were assessed by gas-chromatography mass spectroscopy. Isofuran-to-F2-isoprostane ratios were increased in CKD patients (3.08 ± 0.32 vs. 1.69 ± 0.12 arbitrary units; P < 0.01) indicative of mitochondria-derived oxidative stress. Cutaneous vasodilation was impaired in CKD compared with healthy controls (87 ± 1 vs. 92 ± 1%CVCmax; P < 0.01). Infusion of MitoTempo significantly increased the plateau phase CVC in CKD patients (CKD Ringer vs. CKD MitoTempo: 87 ± 1 vs. 93 ± 1%CVCmax; P < 0.01) to similar levels observed in healthy controls ( P = 0.9). These data provide in vivo evidence that mitochondria-derived reactive oxygen species contribute to microvascular dysfunction in CKD and suggest that mitochondrial dysfunction may be a potential therapeutic target to improve CKD-related vascular dysfunction.


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