Intracerebral hemorrhage (ICH) can lead to the loss of neuronal cells through the response to the hematoma and the release of clot components. Surgical clot removal is a widely employed technique in the clinical management of ICH. However, the analysis of the STICH trial indicates a lack of substantial evidence supporting the superiority of clot evacuation over medical treatment in achieving better outcomes [1,2]. Consequently, these findings have prompted us to focus on improving the resilience of neuronal cells to harmful stimuli when formulating therapeutic approaches for ICH. Multiple research studies have demonstrated the significant neuroprotective properties of human umbilical cord mesenchymal stem cells (hUMSCs).

HUMSCs are preferred for clinical application due to their minimal risk of immune rejection and strong paracrine ability for tissue healing promotion [3,4]. Mesenchymal stem cells (MSCs) can secrete various factors, including growth factors, immunosuppressive factors, exosomes and chemokines, to regulate the cellular immune response to harmful inflammatory stimuli [5].

Exosomes are small membrane vesicles (30–150 nm) released by cells into the extracellular matrix. They transport lipids, proteins and genetic materials. Primarily, they can cross the blood-brain barrier. So, exosomes are essential for intercellular communication and signal transduction [6]. Research has indicated that exosomes from bone mesenchymal stem cells (BMSCs) can improve the prognosis of rats with ICH by reducing inflammation and neuronal apoptosis [7]. Also, exosomes derived from hUMSCs (hUMSCs-Exos) have been shown to prevent apoptosis induced by heat stress and enhance the proliferation of skin cells [8]. Moreover, hUMSCs-Exos ameliorated the mitochondrial dysfunction, aberrant calcium signaling triggered by LPS in vitro, and the cognitive impairments resulting from SE in mice [9]. Recent studies have shown that patients with ICH can exhibit varying types of neuronal damage, including necrosis, apoptosis, ferroptosis and autophagic cell death. The anti-inflammatory properties of MSCs-derived exosomes have been demonstrated as a potential therapy for brain injury [10,11]. However, the precise impact of autophagy regulation on their anti-apoptotic effects on target cells remains incompletely understood.

Autophagy can cause cell death and can also promote cell survival. Maintaining a consistent level of autophagy activation in neural cells is imperative for preserving the integrity of nerve cells in cerebrovascular disorders. Exosomes derived from adipose-derived stem cells effectively regulate autophagy homeostasis in podocytes, preventing renal injury in both MPC5 and spontaneous diabetic mice [12]. The other research indicates that human placenta mesenchymal stem cells enhance autophagy and cell proliferation while inhibiting apoptosis and oxidative stress [13]. Autophagy is activated after ICH, and its inhibition exerts a neuroprotective effect in the ICH model [14]. Research has demonstrated that monosialoteterahexosyl ganglioside (GM1) effectively reduces infarction size and enhances neural function recovery of rats with ischemic brain injury. This positive effect is strongly associated with suppressing cellular autophag [15].

GM1 is crucial for repairing nerves after an injury. Studies have shown that GM1 facilitates synapse development and cell regeneration in the nervous system [16]. Our previous research has found that GM1 could induce the differentiation of hUMSCs into neuron-like cells [17].

It is currently believed that hUMSCs-Exos function by carrying various proteins, RNAs, and cytokines. They can be stimulated in multiple ways, such as altering the cellular environment or drug treatment, to change their internal composition and exhibit new functions. However, the types of substances inside exosomes are diverse, their interactions complex, and the specific molecular mechanisms affecting neural function recovery after ICH are still being explored. Some studies have shown that exosomes can affect neural function recovery post-hemorrhage through anti-apoptotic functions, but the mechanisms related to autophagic cell death are not yet clear. Therefore, through this study, we aim to clarify whether GM1-stimulated hUMSCs-Exos can regulate autophagic cell death in neurons after ICH, thereby elucidating related mechanisms and providing new insights for exosome therapy in treating ICH.

We employed GM1-stimulated hUMSCs-Exos to treat ICH in vivo and in vitro. We observed significant changes in hemorrhagic stroke-related indicators and examined the related cell signaling pathway, autophagy markers, and autophagic flux. Our goal is to determine if GM1-stimulated hUMSCs-Exos can regulate autophagy through the AKT/mTOR pathway and thereby exert protective effects on neurons in ICH.

In this study, we discovered that GM1 can promote a positive feedback loop to enhance hUMSCs differentiation into neuron-like cells through the production of GalNAcT. Additionally, we found that GM1-stimulated hUMSCs-Exos can reduce the size of hematoma, the degree of edema, and the extent of blood-brain barrier damage in rats with ICH, while also improving their behavioral scores, demonstrating therapeutic effects. Lastly, our in vitro experiments revealed that GM1-stimulated hUMSCs-Exos protect neurons by inhibiting apoptosis, reducing ROS production, and restoring mitochondrial membrane potential, potentially through the AKT/mTOR pathway and regulation of autophagy.