Cellular trafficking of thymosin beta-4 in HEPG2 cells following serum starvation.

Pichiri G, Coni P, Nemolato S, Cabras T, Fanari MU, Sanna A, Di Felice E, Messana I, Castagnola M, Faa G

PloS one14 Aug 2013Cited by 6 (Europe PMC)

PMID23967050PMCIDPMC3743897DOI10.1371/journal.pone.0067999PepBankPUB-23967050

Summary

Thymosin beta-4 (Tβ4) is an ubiquitous multi-functional regenerative peptide, related to many critical biological processes, with a dynamic and flexible conformation which may influence its functions and its subcellular distribution. For these reasons, the intracellular localization and trafficking of Tβ4 is still not completely defined and is still under investigation in in vivo as well as in vitro studies. In the current study we used HepG2 cells, a human hepatoma cell line; cells growing in normal conditions with fetal bovine serum expressed high levels of Tβ4, restricted to the cytoplasm until 72 h. At 84 h, a diffuse Tβ4 cytoplasmic immunostaining shifted to a focal perinuclear and nuclear reactivity. In the absence of serum, nuclear reactivity was localized in small granules, evenly dispersed throughout the entire nuclear envelop, and was observed as earlier as at 48 h. Cytoplasmic immunostaining for Tβ4 in HepG2 cells under starvation appeared significantly lower at 48 h and decreased progressively at 72 and at 84 h. At these time points, the decrease in cytoplasmic staining was associated with a progressive increase in nuclear reactivity, suggesting a possible translocation of the peptide from the cytoplasm to the nuclear membrane. The normal immunocytochemical pattern was restored when culture cells submitted to starvation for 84 h received a new complete medium for 48 h. Mass spectrometry analysis, performed on the nuclear and cytosolic fractions of HepG2 growing with and without serum, showed that Tβ4 was detectable only in the cytosolic and not in the intranuclear fraction. These data suggest that Tβ4 is able to translocate from different cytoplasmic domains to the nuclear membrane and back, based on different stress conditions within the cell. The punctuate pattern of nuclear Tβ4 immunostaining associated with Tβ4 absence in the nucleoplasm suggest that this peptide might be localized in the nuclear pores, where it could regulate the pore permeability.

CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study6

No result from this study comes from a test of the peptide.

Natural levels measured6

These results measure the body's own peptide. Nobody was given the peptide. They are not evidence about taking it. They are left out of key results, evidence counts and charts.

01LabEndogenous levelIn vitro (cells)Mechanism
In HepG2 cells grown with serum, Tβ4 was restricted to the cytoplasm until 72 h and shifted to focal perinuclear and nuclear reactivity at 84 h.
In plain wordsIn human liver cancer cells, the cells' own Tβ4 stayed in the cytoplasm for 72 h and then moved toward the nucleus at 84 h.
Peptide
Thymosin beta-4 (human)
Outcome
Not applicableTβ4 localization in HepG2 cells with serum
Study
humann: not reported in source
HepG2 cells
Outcome group
Receptor activity and mechanism · Liver
Source sentences
Summary
In the current study we used HepG2 cells, a human hepatoma cell line; cells growing in normal conditions with fetal bovine serum expressed high levels of Tβ4, restricted to the cytoplasm until 72 h.
1 context sentence(design, population, supporting numbers)
Summary · context
At 84 h, a diffuse Tβ4 cytoplasmic immunostaining shifted to a focal perinuclear and nuclear reactivity.
This result measures the body's own Thymosin beta-4 (human). Nobody was given the peptide. It is not evidence about taking it.
Show in the study text Report a problemFND-2396705001
02LabEndogenous levelIn vitro (cells)Mechanism
In HepG2 cells without serum, nuclear Tβ4 reactivity appeared in small granules as early as 48 h.
In plain wordsIn human liver cancer cells without serum, the cells' own Tβ4 appeared in the nucleus earlier than in cells with serum.
Peptide
Thymosin beta-4 (human)
Outcome
IncreaseNuclear Tβ4 reactivity under serum starvation
Study
humann: not reported in source
HepG2 cells
Comparator
Cells with serum
Outcome group
Receptor activity and mechanism · Liver
Source sentences
Summary
In the absence of serum, nuclear reactivity was localized in small granules, evenly dispersed throughout the entire nuclear envelop, and was observed as earlier as at 48 h.
This result measures the body's own Thymosin beta-4 (human). Nobody was given the peptide. It is not evidence about taking it.
Show in the study text Report a problemFND-2396705002
03LabEndogenous levelIn vitro (cells)Mechanism
In starved HepG2 cells, cytoplasmic Tβ4 immunostaining was significantly lower at 48 h and decreased progressively at 72 and 84 h.
In plain wordsIn human liver cancer cells without serum, the cells' own Tβ4 in the cytoplasm fell over time.
Peptide
Thymosin beta-4 (human)
Outcome
DecreaseCytoplasmic Tβ4 under serum starvation
Study
humann: not reported in source
HepG2 cells
Comparator
Cells with serum
Outcome group
Receptor activity and mechanism · Liver
Source sentences
Summary
Cytoplasmic immunostaining for Tβ4 in HepG2 cells under starvation appeared significantly lower at 48 h and decreased progressively at 72 and at 84 h.
This result measures the body's own Thymosin beta-4 (human). Nobody was given the peptide. It is not evidence about taking it.
Show in the study text Report a problemFND-2396705003
04LabEndogenous levelIn vitro (cells)Mechanism
In starved HepG2 cells, the decrease in cytoplasmic Tβ4 staining was associated with a progressive increase in nuclear reactivity.
In plain wordsIn human liver cancer cells without serum, less of the body's own Tβ4 in the cytoplasm went with more at the nucleus.
Peptide
Thymosin beta-4 (human)
Outcome
IncreaseNuclear Tβ4 reactivity as cytoplasmic staining fell
Study
humann: not reported in source
HepG2 cells
Outcome group
Receptor activity and mechanism · Liver
Source sentences
Summary
At these time points, the decrease in cytoplasmic staining was associated with a progressive increase in nuclear reactivity, suggesting a possible translocation of the peptide from the cytoplasm to the nuclear membrane.
This result measures the body's own Thymosin beta-4 (human). Nobody was given the peptide. It is not evidence about taking it.
Show in the study text Report a problemFND-2396705004
05LabEndogenous levelIn vitro (cells)Mechanism
In HepG2 cells starved for 84 h, a new complete medium for 48 h restored the normal immunocytochemical Tβ4 pattern.
In plain wordsIn human liver cancer cells, adding fresh complete medium brought the normal pattern of the body's own Tβ4 back after starvation.
Peptide
Thymosin beta-4 (human)
Outcome
Not applicableReversal of Tβ4 pattern after complete medium
Study
humann: not reported in source
HepG2 cells
Outcome group
Receptor activity and mechanism · Liver
Source sentences
Summary
The normal immunocytochemical pattern was restored when culture cells submitted to starvation for 84 h received a new complete medium for 48 h.
This result measures the body's own Thymosin beta-4 (human). Nobody was given the peptide. It is not evidence about taking it.
Show in the study text Report a problemFND-2396705005
06LabEndogenous levelIn vitro (cells)Mechanism
Mass spectrometry detected Tβ4 only in the cytosolic fraction of HepG2 cells and not in the intranuclear fraction, with and without serum.
In plain wordsIn human liver cancer cells, mass spectrometry found the cells' own Tβ4 only in the cytosol and not inside the nucleus.
Peptide
Thymosin beta-4 (human)
Outcome
Not applicableTβ4 in nuclear and cytosolic fractions by mass spectrometry
Study
humann: not reported in source
HepG2 cells
Outcome group
Receptor activity and mechanism · Liver
Source sentences
Summary
Mass spectrometry analysis, performed on the nuclear and cytosolic fractions of HepG2 growing with and without serum, showed that Tβ4 was detectable only in the cytosolic and not in the intranuclear fraction.
This result measures the body's own Thymosin beta-4 (human). Nobody was given the peptide. It is not evidence about taking it.
Show in the study text Report a problemFND-2396705006

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

Version 2Current
13 Oct 2026, 01:52 UTC
Study results updated
Version 1
12 Oct 2026, 18:17 UTC
First added · source update from Europe PMC

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