Redox Biology Publication: CB3 Peptide Regulates Oxidative Stress and Neuroinflammation, Emerging as a New Hope for Durable Antiepileptic Effects

Today, we share important research led by Tawfeeq Shekh-Ahmad's team from the Hebrew University of Jerusalem, published in Redox Biology. This study is the first to systematically evaluate the therapeutic potential of the thioredoxin-mimetic peptide TXM-CB3 (CB3) in a temporal lobe epilepsy model. The research found that CB3 can significantly delay epileptogenesis, reduce spontaneous recurrent seizures (SRS) during the chronic phase, and improve epilepsy-associated cognitive dysfunction by modulating key pathways of oxidative stress and neuroinflammation. Notably, CB3 maintained durable antiepileptic effects even after treatment cessation, demonstrating true disease-modifying therapy characteristics. This offers new hope for approximately 30-40% of patients with drug-resistant epilepsy.

01 Research Background

Epilepsy is a common chronic neurological disorder affecting approximately 70 million people worldwide, characterized by recurrent unprovoked seizures. Although several antiseizure medications are available, about 30-40% of patients develop refractory epilepsy. Current drugs primarily target symptom control (suppressing neuronal hyperexcitability) and cannot prevent the development and progression of the disease (epileptogenesis). Oxidative stress and neuroinflammation are recognized as core pathological mechanisms driving epileptogenesis and drug resistance. They form a self-sustaining vicious cycle that persistently leads to neuronal hyperexcitability, epilepsy-associated neuronal death, and exacerbates disease progression. Therefore, targeting this interconnected pathological duo of oxidative stress and neuroinflammation to develop therapies with disease-modifying potential is an urgent need and a key direction in current epilepsy research. The thioredoxin reductase/thioredoxin system is a crucial hub for regulating intracellular redox balance and neuroinflammatory signaling. TXM-CB3 is a thioredoxin-mimetic peptide containing a tripeptide structure (Ac-Cys-Pro-Cys-NH2). Previous studies have shown its ability to inhibit oxidative stress-induced inflammatory and apoptotic signaling in models like traumatic brain injury. However, the efficacy of CB3 in epilepsy and its potential disease-modifying properties were previously unknown.

02 Innovative Highlights

First Confirmation of CB3's Dual Inhibition of Oxidative Stress and Neuroinflammation in an Epilepsy Model:

The study initially confirmed in an in vitrolow-magnesium-induced epileptiform activity model that CB3 pretreatment concentration-dependently reduced reactive oxygen species levels, significantly downregulated mRNA expression of pro-inflammatory cytokines (IL-6, IL-1β, TNF-α), and upregulated the anti-inflammatory cytokine IL-10. This laid a solid mechanistic foundation for subsequent in vivostudies.

Systematic Evaluation of CB3's Therapeutic Effects During Early Epileptogenesis and the Chronic Phase:

The study design included two core cohorts: Cohort I received early CB3 intervention after status epilepticus to assess its "anti-epileptogenic" potential; Cohort II received CB3 treatment during the established chronic epilepsy phase to evaluate its "disease-modifying" effects. This design comprehensively reveals CB3's role at different disease stages.

Comprehensive Assessment of Three Core Indicators: Seizures, Neuroprotection, and Behavior:

The research not only focused on CB3's impact on SRS frequency and burden but also histologically assessed its protective effect on hippocampal neuron integrity. Furthermore, it utilized a battery of behavioral tests (open field, elevated plus maze, novel object recognition, T-maze) to comprehensively evaluate its improvement of cognitive function and anxiety-like behaviors.

Reveal of CB3's Sustained Residual Effects, Highlighting Its Disease-Modifying Characteristic:

The study found that, regardless of early intervention or chronic-phase treatment, the seizure-reducing effect of CB3 persisted for several weeks after only a 2-week treatment period ceased. This sustained efficacy beyond the treatment cycle is a key distinguishing feature from traditional antiseizure medications that only temporarily control symptoms, suggesting CB3 may genuinely alter the disease's natural course.

03 Results and Discussion

3.1 CB3 Effectively Suppresses Oxidative Stress and Inflammatory Response in Epileptiform Activity 

In primary cortical neuron-glia cultures, epileptiform activity was induced under low magnesium conditions. As shown in Figure 1, CB3 pretreatment significantly inhibited the increase in dihydroethidium (DHE) fluorescence intensity caused by epileptiform activity, indicating its mitigation of oxidative stress. Concurrently, qRT-PCR results showed that CB3 significantly reduced mRNA levels of pro-inflammatory factors IL-6, IL-1β, TNF-α and elevated levels of the anti-inflammatory factor IL-10 (Fig. 1).

Fig. 1. CB3 modulates oxidative activity and cytokine expression in low Mg2+-induced epileptiform activity.

3.2 Early CB3 Intervention Delays Epileptogenesis and Reduces Seizure Burden

In the kainic acid-induced status epilepticus model (Cohort I), early administration of CB3 (20 mg/kg/day, i.p., for 2 weeks) demonstrated significant anti-epileptogenic effects. Compared to the Vehicle group, animals in the CB3-treated group showed a significantly prolonged latency to the first spontaneous seizure, significantly reduced seizure frequency and cumulative seizure burden over the entire 12-week observation period, and shorter seizure durations. The cumulative probability of animals remaining seizure-free was also significantly higher in the CB3-treated group (Fig. 2).

Fig. 2. CB3 suppresses epilepsy development and overall seizure burden following SE.

3.3 CB3 Improves Cognitive Function and Reduces Anxiety-Like Behaviors During Epileptogenesis

Behavioral tests conducted at week 5 post-status epilepticus (i.e., 3 weeks after CB3 cessation) showed that CB3-treated animals traveled a greater total distance, entered the center zone more frequently and spent more time there in the open field test. They also spent more time and entered the open arms more frequently in the elevated plus maze, indicating reduced anxiety-like behavior. CB3-treated animals performed better in the T-maze spontaneous alternation test, suggesting protected spatial working memory (Fig. 3).

Fig. 3. CB3 prevents cognitive declines associated with epilepsy development.

3.4 CB3 Protects Hippocampal Neuron Integrity and Reduces Oxidative DNA Damage

Nissl staining showed that early CB3 intervention significantly reduced neuron loss in the hippocampal CA1 and CA3 regions following status epilepticus. Immunofluorescence staining further revealed that CB3 treatment decreased the fluorescence intensity of the oxidative DNA damage marker 8-OHdG in hippocampal CA1 neurons, indicating its alleviation of epilepsy-associated oxidative stress damage (Fig. 4).

Fig. 4. CB3 exert a sustained protective effect on hippocampal neurons following recurrent seizure activity.

3.5 CB3 Treatment Effectively Ameliorates Established Chronic Epilepsy

In the chronic phase epilepsy animal model (Cohort II), a 2-week CB3 treatment course still significantly reduced the frequency and cumulative burden of SRS. This effect persisted for up to 4 weeks after treatment cessation, demonstrating CB3's positive modifying effect on established epilepsy (Fig. 5).

Fig. 5. CB3 treatment suppresses recurrent seizure activity and seizure progression in epileptic animals.

3.6 Limitations of CB3's Effects on Behavior in Chronic Phase Epilepsy

In the chronic phase treatment, CB3 only showed a trend towards reducing anxiety-like behaviors (improvements in open field and elevated plus maze) but failed to reverse cognitive deficits in the novel object recognition and T-maze tests. This suggests that early intervention may be more critical for protecting cognitive function.

04 Conclusion and Future Perspectives

This study provides strong evidence that the thioredoxin-mimetic peptide CB3 has significant disease-modifying potential in a preclinical epilepsy model. Its core value lies in achieving multiple therapeutic benefits—inhibiting epileptogenesis, reducing seizure burden in the chronic phase, protecting neurons, and partially improving behavioral comorbidities—through dual modulation of the key pathological drivers: oxidative stress and neuroinflammation, with sustained effects.

CB3 represents a new paradigm distinct from traditional antiseizure drugs, shifting focus from targeting symptoms (neuronal excitability) to targeting the root disease drivers (oxidative stress/neuroinflammation). Future research could focus on: ① delving deeper into the specific molecular targets and signaling pathways of CB3; ② conducting rigorous pharmacokinetic and safety evaluations to prepare for clinical translation; ③ exploring combination strategies with existing antiseizure medications, especially for patients with refractory epilepsy; and ④ validating its efficacy in different models, including female animals, to examine sex differences. In conclusion, CB3 brings new hope for developing therapies capable of altering the course of epilepsy, potentially offering a new treatment option for millions of patients worldwide with drug-resistant epilepsy.

Singh PK, Maurya S, Saadi A, Sandouka S, Zhang T, Kadosh O, Sheeni Y, Martin V, Atlas D, Shekh-Ahmad T. Thioredoxin-mimetic peptide attenuates epilepsy progression and neurocognitive deficits. Redox Biol. 2026 Mar;90:104021. doi: 10.1016/j.redox.2026.104021.