Lactiplantibacillus plantarum CRL1506 ameliorates poly(I:C)-induced acute liver injury through cell wall-dependent modulation of inflammatory and antiviral immune responses.
Lorenzo Pisarello M, Baillo A, et al. • Food & function • 2026
Oral administration of Lactiplantibacillus plantarum CRL1506 significantly reduced serum transaminase levels and attenuated histopathological liver damage in a murine model of poly(I:C)-induced acute liver injury through cell wall-dependent modulation of inflammatory and antiviral immune responses, with lipoteichoic acid playing a critical role.
Key Findings
Results
Oral administration of L. plantarum CRL1506 significantly reduced serum transaminase levels following poly(I:C)-induced acute liver injury.
Wild-type CRL1506 strain conferred significant protection against poly(I:C)-induced liver damage as measured by serum transaminase levels.
The surface-modified ΔdltD mutant strain failed to reduce transaminase levels, indicating protection is cell wall-dependent.
Poly(I:C), a synthetic analog of viral double-stranded RNA, was used to mimic virus-induced acute liver damage in a murine model.
The reduction in transaminase levels is a standard biomarker indicator of reduced hepatocellular injury.
Results
L. plantarum CRL1506 attenuated histopathological liver damage induced by poly(I:C) challenge in mice.
Wild-type CRL1506 strain significantly reduced histopathological signs of liver damage after poly(I:C) challenge.
The ΔdltD mutant strain did not confer comparable histopathological protection.
Histopathological assessment was used alongside serum transaminase measurements to confirm hepatoprotective effects.
The murine model employed poly(I:C) administration to simulate viral acute liver injury.
Results
CRL1506 treatment produced marked modulation of hepatic inflammatory mediators, including reduction of proinflammatory cytokines.
The wild-type CRL1506 strain significantly reduced proinflammatory cytokines in the liver following poly(I:C) challenge.
The ΔdltD mutant strain failed to achieve equivalent modulation of the hepatic cytokine profile.
Protective effects were associated with improvements in antiviral factors and regulatory cytokines in addition to reduction of proinflammatory mediators.
The modulation of the liver cytokine profile highlights a fine-tuning of both inflammatory and antiviral immune pathways.
Results
Lipoteichoic acid, a component of the bacterial cell wall, plays a critical role in mediating the immunobiotic and hepatoprotective effects of L. plantarum CRL1506.
The ΔdltD mutant strain is a surface-modified strain with altered lipoteichoic acid configuration.
The ΔdltD mutant strain failed to confer protection against liver injury, failed to reduce transaminase levels, and failed to modulate the hepatic cytokine profile.
These results highlight the role of lipoteichoic acid in the regulation of the immune system by L. plantarum CRL1506.
Bacterial surface configuration was identified as a key determinant of immunobiotic efficacy.
Results
The ΔdltD mutant strain of L. plantarum CRL1506 failed to confer protection against poly(I:C)-induced acute liver injury.
Unlike the wild-type CRL1506 strain, the ΔdltD mutant did not significantly reduce serum transaminase levels.
The mutant strain also failed to attenuate histopathological liver damage.
No significant modulation of the hepatic inflammatory or antiviral cytokine profile was observed with the mutant strain.
The ΔdltD mutation alters cell surface lipoteichoic acid, indicating this surface component is required for hepatoprotective immunomodulation.
Results
L. plantarum CRL1506 improved antiviral factors and regulatory cytokines in the liver in the context of poly(I:C) challenge.
Beyond reducing proinflammatory cytokines, CRL1506 treatment was associated with improvements in antiviral factors in the liver.
Regulatory cytokines were also improved in the hepatic environment following CRL1506 oral administration.
These effects collectively indicate a balanced immunomodulatory action rather than simple suppression of immune responses.
The ΔdltD mutant did not replicate these antiviral and regulatory improvements.
Discussion
Immunobiotic strains administered orally can exert beneficial immunomodulatory effects in extraintestinal tissues such as the liver.
The study provides evidence that orally administered L. plantarum CRL1506 influences immune responses beyond the gut.
The hepatoprotective effects were demonstrated in a poly(I:C)-induced murine model of acute liver injury.
This supports increasing evidence that immunobiotics can influence extraintestinal immune responses.
The findings underscore the potential of immunobiotic strains as functional dietary interventions to mitigate acute liver inflammation triggered by viral components.
What This Means
This research suggests that a specific probiotic bacterium, Lactiplantibacillus plantarum CRL1506, can help protect the liver from damage caused by viral infection-like conditions. In laboratory mice, scientists simulated acute viral liver disease using a synthetic molecule called poly(I:C), which mimics the kind of signal that the immune system detects during a viral infection. Mice that received the probiotic orally before the challenge showed significantly less liver damage — as measured by both blood markers of liver injury (transaminases) and microscopic examination of liver tissue — compared to untreated mice. The probiotic appeared to work by fine-tuning the immune response in the liver, reducing harmful inflammatory signals while preserving or improving the body's antiviral defenses and regulatory mechanisms.
A key part of this study was comparing the normal CRL1506 strain with a genetically modified version called the ΔdltD mutant, which has an altered bacterial surface due to changes in a component called lipoteichoic acid. Strikingly, this mutant strain provided no liver protection and failed to modulate immune responses in the liver, despite being otherwise similar to the original strain. This finding identifies lipoteichoic acid — part of the bacteria's outer surface — as a critical structural feature responsible for the immune-modulating and liver-protective effects, demonstrating that the physical structure of the probiotic's cell wall matters enormously for its beneficial activity.
This research suggests that certain probiotic bacteria, when consumed orally, may be able to influence immune activity not just in the gut but also in distant organs like the liver. This could be relevant for understanding how diet and gut bacteria interact with the immune system during viral infections that affect the liver. The study highlights the potential for carefully selected probiotic strains to serve as dietary tools to help reduce excessive liver inflammation during viral illness, though this research was conducted in mice and further studies would be needed to understand whether these effects translate to humans.
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Lorenzo Pisarello M, Baillo A, Elean M, Albarracín L, Arellano-Arriagada L, Suda Y, et al.. (2026). Lactiplantibacillus plantarum CRL1506 ameliorates poly(I:C)-induced acute liver injury through cell wall-dependent modulation of inflammatory and antiviral immune responses.. Food & function. https://doi.org/10.1039/d6fo01160h