Summary of Study ST002277

This data is available at the NIH Common Fund's National Metabolomics Data Repository (NMDR) website, the Metabolomics Workbench, https://www.metabolomicsworkbench.org, where it has been assigned Project ID PR001458. The data can be accessed directly via it's Project DOI: 10.21228/M8898H This work is supported by NIH grant, U2C- DK119886.

See: https://www.metabolomicsworkbench.org/about/howtocite.php

This study contains a large results data set and is not available in the mwTab file. It is only available for download via FTP as data file(s) here.

Study ID	ST002277
Study Title	Skin-to-blood pH shift triggers metabolome and proteome global remodelling in Staphylococcus epidermidis
Study Type	NMR Metabolomics combine with proteomics to study pH adaptation of Staphylococcus epidermidis 19N
Study Summary	Staphylococcus epidermidis (SE) is one of the most common bacteria of the human skin microbiota. Despite its role as a commensal, SE has emerged as an opportunistic pathogen, associated with 80% of medical devices related infections. Moreover, these bacteria are extremely difficult to treat due to their ability to form biofilms and accumulate resistance to almost all classes of antimicrobials developed so far. Thus new preventive and therapeutic strategies are urgently needed. In spite of its clinical importance, the molecular mechanisms associated with SE colonisation and disease are still poorly understood. A deeper understanding of the metabolic and cellular processes associated with response to environmental factors characteristic of SE ecological niches in health and disease might provide new clues on colonisation and disease processes. Here we studied the impact of pH conditions, mimicking the skin pH (5.5) and blood pH (7.4), in a S. epidermidis commensal strain, belonging to the B clonal lineage, by means of next-generation proteomics and 1H NMR-based metabolomics. Moreover, we evaluated the metabolic changes occurring when a sudden pH change arise, simulating the skin barrier break produced by a catheter. We found that exposure of S. epidermidis to skin pH induced oxidative phosphorylation and biosynthesis of peptidoglycan, lipoteichoic acids and betaine. In contrast, at blood pH, the incorporation of monosaccharides and its oxidation by glycolysis and fermentation was promoted. Additionally, several proteins related to virulence and immune evasion, namely extracellular proteases and membrane iron transporters were more abundant at blood pH. In the situation of an abrupt skin-to-blood pH shift we observed the decrease in the osmolyte betaine and changes in the levels of several metabolites and proteins involved in redox cell homeostasis. Our results suggest that at the skin pH S. epidermidis cells are metabolically more active and adhesion is promoted, while at blood pH, metabolism is tuned down and cells have a more virulent profile. pH increase during commensal-to-pathogen conversion appears to be a critical environmental signal to the remodelling of the S. epidermidis metabolism towards a more pathogenic state. Targeting S. epidermidis proteins induced by a low alkaline pH and local acidification of medical devices microenvironment might be new strategies to treat and prevent S. epidermidis infections.
Institute	ITQB NOVA
Laboratory	Proteomics of Non-Model Organisms
Last Name	Gonçalves
First Name	Luís
Address	Avenida Republica, Oeiras, Not USCanada, 2780-157 Oeiras, Portugal
Email	lgafeira@itqb.unl.pt
Phone	214469464
Submit Date	2022-07-14
Num Groups	3
Raw Data Available	Yes
Raw Data File Type(s)	fid
Analysis Type Detail	NMR
Release Date	2023-01-16
Release Version	1

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Project:

Project ID:	PR001458
Project DOI:	doi: 10.21228/M8898H
Project Title:	Skin-to-blood pH shift triggers metabolome and proteome global remodelling in Staphylococcus epidermidis
Project Summary:	Staphylococcus epidermidis (SE) is one of the most common bacteria of the human skin microbiota. Despite its role as a commensal, SE has emerged as an opportunistic pathogen, associated with 80% of medical devices related infections. Moreover, these bacteria are extremely difficult to treat due to their ability to form biofilms and accumulate resistance to almost all classes of antimicrobials developed so far. Thus new preventive and therapeutic strategies are urgently needed. In spite of its clinical importance, the molecular mechanisms associated with SE colonisation and disease are still poorly understood. A deeper understanding of the metabolic and cellular processes associated with response to environmental factors characteristic of SE ecological niches in health and disease might provide new clues on colonisation and disease processes. Here we studied the impact of pH conditions, mimicking the skin pH (5.5) and blood pH (7.4), in a S. epidermidis commensal strain, belonging to the B clonal lineage, by means of next-generation proteomics and 1H NMR-based metabolomics. Moreover, we evaluated the metabolic changes occurring when a sudden pH change arise, simulating the skin barrier break produced by a catheter. We found that exposure of S. epidermidis to skin pH induced oxidative phosphorylation and biosynthesis of peptidoglycan, lipoteichoic acids and betaine. In contrast, at blood pH, the incorporation of monosaccharides and its oxidation by glycolysis and fermentation was promoted. Additionally, several proteins related to virulence and immune evasion, namely extracellular proteases and membrane iron transporters were more abundant at blood pH. In the situation of an abrupt skin-to-blood pH shift we observed the decrease in the osmolyte betaine and changes in the levels of several metabolites and proteins involved in redox cell homeostasis. Our results suggest that at the skin pH S. epidermidis cells are metabolically more active and adhesion is promoted, while at blood pH, metabolism is tuned down and cells have a more virulent profile. pH increase during commensal-to-pathogen conversion appears to be a critical environmental signal to the remodelling of the S. epidermidis metabolism towards a more pathogenic state. Targeting S. epidermidis proteins induced by a low alkaline pH and local acidification of medical devices microenvironment might be new strategies to treat and prevent S. epidermidis infections.
Institute:	ITQB NOVA
Last Name:	Gonçalves
First Name:	Luís
Address:	Avenida Republica, Oeiras, Not USCanada, 2780-157 Oeiras, Portugal
Email:	lgafeira@itqb.unl.pt
Phone:	214469464

Subject:

Subject ID:	SU002363
Subject Type:	Bacteria
Subject Species:	Staphylococcus epidermidis
Taxonomy ID:	1282
Genotype Strain:	Staphylococcus epidermidis 19N

Factors:

Subject type: Bacteria; Subject species: Staphylococcus epidermidis (Factor headings shown in green)

mb_sample_id	local_sample_id	class
SA218333	SE_22	N55
SA218334	SE_12	N55
SA218335	SE_29	N55
SA218336	SE_31	N55
SA218337	SE_48	N55
SA218338	SE_44	N55
SA218339	SE_39	N55
SA218340	SE_34	N57
SA218341	SE_28	N57
SA218342	SE_18	N57
SA218343	SE_16	N57
SA218344	SE_27	N57
SA218345	SE_19	N57
SA218346	SE_23	N57
SA218347	SE_20	N57
SA218348	SE_50	N77
SA218349	SE_8	N77
SA218350	SE_6	N77
SA218351	SE_30	N77
SA218352	SE_2	N77
SA218353	SE_37	N77
SA218354	SE_4	N77
SA218355	SE_43	N77

Showing results 1 to 23 of 23

Showing results 1 to 23 of 23

Collection:

Collection ID:	CO002356
Collection Summary:	The Staphylococcus epidermidis 19N strain was collected from the anterior nares of a healthy person in Portugal in 2001. This strain was previously characterised by whole genome sequencing and belongs to clonal lineage B. A single colony from a S. epidermidis 19N strain culture grown O/N at 37ºC (TSA, BactoTM), was used to pre-inoculate Tryptic Soy Broth (TSB) medium with two different pH (5.5 and 7.4) that was incubated overnight at 37ºC under agitation. Pre-inoculums were adjusted either to pH 5.5 or pH 7.4, with hydrochloric acid. In this work, three pH transitions from pre-inoculum to inoculum were assayed. S. epidermidis pre-inoculums and the growth were performed at medium with pH 7.4, to mimic the blood pH; and pH 5.5, to mimic the skin pH. The pre-inoculum cellular density was adjusted to 0.06 (OD600) (aprox.1.5x108 CFU/mL) and used to inoculate fresh medium in the three conditions depicted in Figure 1, simulating S. epidermidis at skin and blood and a pH shock endured by S. epidermidis during the infection process from skin to blood transition. The cell cultures incubated at 37ºC with 225 rpm were followed by OD600 and recovered at mid-exponential phase for further analysis.
Sample Type:	Staphylococcus epidermidis intracellular
Storage Conditions:	-80℃

Treatment:

Treatment ID:	TR002375
Treatment Summary:	In this work, three pH transitions from pre-inoculum to inoculum were assayed. S. epidermidis pre-inoculums and the growth were performed at medium with pH 7.4, to mimic the blood pH; and pH 5.5, to mimic the skin pH. The pre-inoculum cellular density was adjusted to 0.06 (OD600) (aprox.1.5x108 CFU/mL) and used to inoculate fresh medium in the three conditions depicted in Figure 1, simulating S. epidermidis at skin and blood and a pH shock endured by S. epidermidis during the infection process from skin to blood transition. The cell cultures incubated at 37ºC with 225 rpm were followed by OD600 and recovered at mid-exponential phase for further analysis. Pre-inocula were prepared in TSB medium at pH 5.5 or 7.4. Inocula at pH 5.5 was used for the cultures grown at 5.5 (N55) and 7.4 (N57), and the inoculum at pH 7.4 for the culture at the same pH (N77). The cells were harvested at mid-exponential phase.

Treatment ID:

TR002375

Treatment Summary:

In this work, three pH transitions from pre-inoculum to inoculum were assayed. S. epidermidis pre-inoculums and the growth were performed at medium with pH 7.4, to mimic the blood pH; and pH 5.5, to mimic the skin pH. The pre-inoculum cellular density was adjusted to 0.06 (OD600) (aprox.1.5x108 CFU/mL) and used to inoculate fresh medium in the three conditions depicted in Figure 1, simulating S. epidermidis at skin and blood and a pH shock endured by S. epidermidis during the infection process from skin to blood transition. The cell cultures incubated at 37ºC with 225 rpm were followed by OD600 and recovered at mid-exponential phase for further analysis. Pre-inocula were prepared in TSB medium at pH 5.5 or 7.4. Inocula at pH 5.5 was used for the cultures grown at 5.5 (N55) and 7.4 (N57), and the inoculum at pH 7.4 for the culture at the same pH (N77). The cells were harvested at mid-exponential phase.

Sample Preparation:

Sampleprep ID:	SP002369
Sampleprep Summary:	Cells were recovered at mid-exponential phase from 100 mL cultures following a protocol adapted from Somerville & Powers (Somerville and Powers 2014). Eight biological replicates of each independent growth condition were obtained. Cells were harvested by centrifugation at 5000 x g for 5 min at 4ºC. Cells were washed with 20 mM phosphate buffer pH 7.2-7.4 and centrifuged for 1 min at 13,000 rpm. Cell pellet was suspended in the same buffer with a final OD600 of 20 and stored at -80ºC for further metabolite extraction. Cells were thawed in a water bath at room temperature and 750 µL of 60% methanol were added and subjected to three freeze-thaw cycles using liquid nitrogen. Extracted samples were centrifuged at 21,000 g for 5 min at 4ºC. The extraction process on the pellets was repeated twice. The supernatants were kept and stored together at -20ºC overnight and dried in a SpeedVac. Dried samples were dissolved in: 750 µL phosphate buffer (33 mM, pH 7.0 in D2O with 2 mM of sodium azide) with 0.21 mM of 3-(trimethylsilyl)propionic-2,2,3,3-d4 (TSP). The suspensions were centrifuged at 21,000 g for 5 min at 4ºC and the resulting supernatants were then transferred to 5 mm NMR tubes.

Sampleprep ID:

SP002369

Sampleprep Summary:

Cells were recovered at mid-exponential phase from 100 mL cultures following a protocol adapted from Somerville & Powers (Somerville and Powers 2014). Eight biological replicates of each independent growth condition were obtained. Cells were harvested by centrifugation at 5000 x g for 5 min at 4ºC. Cells were washed with 20 mM phosphate buffer pH 7.2-7.4 and centrifuged for 1 min at 13,000 rpm. Cell pellet was suspended in the same buffer with a final OD600 of 20 and stored at -80ºC for further metabolite extraction. Cells were thawed in a water bath at room temperature and 750 µL of 60% methanol were added and subjected to three freeze-thaw cycles using liquid nitrogen. Extracted samples were centrifuged at 21,000 g for 5 min at 4ºC. The extraction process on the pellets was repeated twice. The supernatants were kept and stored together at -20ºC overnight and dried in a SpeedVac. Dried samples were dissolved in: 750 µL phosphate buffer (33 mM, pH 7.0 in D2O with 2 mM of sodium azide) with 0.21 mM of 3-(trimethylsilyl)propionic-2,2,3,3-d4 (TSP). The suspensions were centrifuged at 21,000 g for 5 min at 4ºC and the resulting supernatants were then transferred to 5 mm NMR tubes.

Analysis:

Analysis ID:	AN003721
Analysis Type:	NMR
Software Version:	Bruker TopSpin 3.2
Num Factors:	3
Num Metabolites:	43
Units:	nanomoles

NMR:

NMR ID:	NM000248
Analysis ID:	AN003721
Instrument Name:	Bruker Avance II+ 800 MHz
Instrument Type:	FT-NMR
NMR Experiment Type:	1D-1H
Spectrometer Frequency:	800
NMR Probe:	5 mm TXI-Z H/C/N/-D
NMR Solvent:	D2O
NMR Tube Size:	5 mm
Shimming Method:	Topshim
Temperature:	25
Number Of Scans:	256
Dummy Scans:	4
Chemical Shift Ref Std:	TSP
NMR Results File:	NMR_SE