Peripheral blood HOIP and OTULIN expression levels were significantly higher in AIS patients than healthy controls, with HOIP independently associated with stroke severity and poor functional outcome, suggesting these molecules 'may serve as candidate biomarkers associated with stroke severity in AIS, while HOIP may provide additional prognostic information for functional outcome.'
Key Findings
Results
Peripheral blood HOIP and OTULIN expression levels were significantly higher in acute ischemic stroke patients than in healthy controls.
100 AIS patients were compared to 100 age- and sex-matched healthy controls.
Both HOIP and OTULIN mRNA levels were elevated in AIS patients (P < 0.001 for both).
HOIL-1L and SHARPIN (other LUBAC components) were also measured but HOIP and OTULIN were the focus of regression analyses.
Expression was quantified using quantitative reverse transcription polymerase chain reaction (qRT-PCR) from peripheral blood.
Results
Immunofluorescence of cortical autopsy specimens suggested increased LUBAC and OTULIN expression in the peri-ischemic cortex.
Immunofluorescence was performed on cortical autopsy specimens from two AIS cases.
Elevated expression was observed specifically in peri-ischemic cortex regions.
This finding provided histological context for the peripheral blood biomarker investigation.
The small sample size (n=2) limits the generalizability of the tissue-level findings.
Results
After adjustment for potential confounders, HOIP was independently positively associated with stroke severity as measured by NIHSS at admission.
Regression coefficient β = 1.928, P < 0.001.
Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) at admission.
The association remained significant after adjustment for confounders in multivariate regression.
Results
After adjustment for potential confounders, OTULIN was independently negatively associated with stroke severity but not independently associated with poor functional outcome.
OTULIN association with severity: β = -1.060, P < 0.001, indicating higher OTULIN expression was associated with lower NIHSS scores.
OTULIN's independent association with poor outcome (mRS >2) was not statistically significant (P = 0.119).
Functional outcome was assessed using the modified Rankin Scale (mRS) at 90 ± 7 days.
Poor outcome was defined as mRS > 2.
Results
HOIP was independently associated with poor functional outcome at 90 days after adjustment for confounders.
OR = 5.360, P = 0.013 for poor outcome (mRS > 2).
Functional outcome was evaluated at 90 ± 7 days post-stroke.
The association remained significant after multivariate adjustment.
Results
Interaction analysis revealed a significant interaction between HOIP and OTULIN on stroke severity.
A HOIP × OTULIN interaction term was applied to assess effect modification.
The interaction was statistically significant for stroke severity.
The interaction term for poor outcome was not reported as significant.
This suggests OTULIN may modify the relationship between HOIP expression and stroke severity.
Results
HOIP demonstrated good discriminative ability for poor functional outcome and improved the clinical prediction model when added to clinical variables.
HOIP alone had AUC = 0.832 for discriminating poor outcome (mRS > 2) by ROC analysis.
Adding HOIP to the clinical model increased the AUC from 0.846 to 0.907.
Addition of HOIP further improved model calibration and clinical net benefit.
Discrimination was assessed using receiver operating characteristic (ROC) analysis.
Methods
The study enrolled 100 AIS patients and 100 age- and sex-matched healthy controls in a prospective cohort design.
This was a prospective cohort study.
Controls were matched for age and sex.
LUBAC components measured included HOIP, HOIL-1L (heme-oxidized IRP2 ubiquitin ligase 1L), and SHARPIN (SHANK-associated RH domain interactor).
Primary exposure variables were peripheral blood mRNA levels quantified by qRT-PCR.
What This Means
This research investigated whether two proteins involved in inflammation regulation — HOIP (part of the LUBAC complex) and OTULIN — could serve as blood-based markers to predict stroke severity and recovery. The study measured these proteins in the blood of 100 stroke patients and compared them to 100 healthy individuals, while also examining brain tissue from two stroke patients who had undergone autopsy. Both HOIP and OTULIN were found at higher levels in the blood of stroke patients compared to healthy controls, and elevated HOIP levels in brain tissue near the stroke-affected area were also observed.
The key findings were that higher HOIP levels in the blood were linked to more severe strokes on admission and to worse functional outcomes three months later, even after accounting for other factors like age, medical history, and other clinical variables. Higher OTULIN levels, by contrast, were associated with less severe strokes, though OTULIN did not significantly predict functional recovery at three months. Notably, HOIP and OTULIN appeared to interact with each other in influencing stroke severity. When HOIP was added to standard clinical information in a prediction model, the model's ability to identify patients likely to have poor recovery improved substantially, with the accuracy score increasing from 0.846 to 0.907.
This research suggests that measuring HOIP and OTULIN in the blood of stroke patients shortly after hospital admission could provide doctors with useful additional information about how severe a stroke is and how well a patient might recover over the following months. These proteins are involved in a cellular signaling pathway (the linear ubiquitination system) that regulates inflammation and cell death, which are both important processes in stroke brain injury. Further research in larger populations would be needed to validate these findings before clinical application.
Chen W, Chen Z, Chen H, Li J, Xie J, Chen X, et al.. (2026). Association of peripheral blood LUBAC and OTULIN expression with severity and outcome in acute ischemic stroke: a prospective cohort study.. Frontiers in immunology. https://doi.org/10.3389/fimmu.2026.1792936