Salvianolic acid B alleviates comorbid pain in depression induced by chronic restraint stress through inhibiting GABAergic neuron excitation via an ERK-CREB-BDNF axis-dependent mechanism

Network pharmacology and experimental evidence: ERK/CREB/BDNF signaling pathway is involved in the antidepressive roles of Kaiyu Zhishen decoction

ETHNOPHARMACOLOGICAL RELEVANCE

Major Depressive Disorder (MDD) emerges as a complex psychosomatic condition, notable for its considerable suicidality and mortality rates. Increasing evidence suggests the efficacy of Chinese herbal medicine in mitigating depression symptoms and offsetting the adverse effects associated with conventional Western therapeutics. Notably, clinical trials have revealed the adjunctive antidepressant potential of Kaiyu Zhishen Decoction (KZD) alongside Western medication. However, the standalone antidepressant efficacy of KZD and its underlying mechanisms merit in-depth investigation.

AIM OF THE STUDY

This research aims to elucidate the impact of KZD on MDD and delineate its mechanistic pathways through integrated network pharmacological assessments and empirical in vitro and in vivo analyses.

MATERIALS AND METHODS

To ascertain the optimal antidepressant dosage and mechanism of KZD, a Chronic Unpredictable Mild Stress (CUMS)-induced depression model in mice was established to evaluate depressive behaviors. High-Performance Liquid Chromatography (HPLC) and network pharmacological approaches were employed to predict KZD's antidepressant mechanisms. Subsequently, hippocampal samples were subjected to 4D-DIA proteomic sequencing and validated through Western blot, immunofluorescence, Nissl staining, and pathway antagonist applications. Additionally, cortisol-stimulated PC12 cells were utilized to simulate neuronal damage, analyzing protein and mRNA levels of MAPK-related signals and cell proliferation markers.

RESULTS

The integration of network pharmacology and HPLC identified kaempferol and quercetin as KZD's principal active compounds for MDD treatment. Proteomic and network pharmacological KEGG pathway analyses indicated the MAPK signaling pathway as a critical regulatory mechanism for KZD's therapeutic effect on MDD. KZD was observed to mitigate CUMS-induced upregulation of p-ERK/ERK, CREB, and BDNF protein expressions in hippocampal cells by attenuating oxidative stress, thereby ameliorating neuronal damage and exerting antidepressant effects. The administration of PD98059 counteracted KZD's improvements in depression-like behaviors and downregulated p-ERK/ERK and BDNF protein expressions in the hippocampus.

CONCLUSIONS

This investigation corroborates KZD's pivotal, dose-dependent role in antidepressant activity. Both in vivo and in vitro experiments demonstrate KZD's capacity to modulate the ERK-CREB-BDNF signaling pathway by diminishing ROS expression induced by oxidative stress, enhancing neuronal repair, and thus, manifesting antidepressant properties. Accordingly, KZD represents a promising herbal candidate for further antidepressant research.

Prokineticin-2 Participates in Chronic Constriction Injury-Triggered Neuropathic Pain and Anxiety via Regulated by NF-κB in Nucleus Accumbens Shell in Rats

Neuropathic pain (NP) is an intractable pain that results from primary nervous system injury and dysfunction. Herein, we demonstrated in animal models that peripheral nerve injury induced enhanced pain perception and anxiety-like behaviors. According to previous reports, nucleus accumbens (NAc) shell is required for complete expression of neuropathic pain behaviors and mood alternations, we found the elevated mRNA and protein level of Prokineticin-2 (Prok2) in the NAc shell after Chronic Constriction Injury (CCI). Prok2 knockdown in the NAc shell reversed NP and anxiety-like behaviors in rats, indicating that Prok2 might play a fundamental role in NP and anxiety co-morbidity. CCI significantly enhanced Prok2 co-expression with NF-κB P-p65 in comparison with control animals. In addition to reversing the established nociceptive hypersensitivities and anxiety simultaneously, NAc microinjection of NF-κB siRNA or specific inhibitor PDTC reversed Prok2 upregulation. Besides, Prok2 was significantly decreased in vitro when co-transfected with si-NF-κB. Dual-Luciferase assay showed NF-κB directly activated Prok2 gene transcriptional activity. Overall, these findings provide new insights into the neurobiological mechanisms behind NP and comorbid anxiety. The NF-κB/Prok2 pathway could be a potential therapeutic target for NP and anxiety disorders.

Targeting autophagy to counteract neuroinflammation: A novel antidepressant strategy

Depression is a common disease that affects physical and mental health and imposes a considerable burden on afflicted individuals and their families worldwide. Depression is associated with a high rate of disability and suicide. It causes a severe decline in productivity and quality of life. Unfortunately, the pathophysiological mechanisms underlying depression have not been fully elucidated, and the risk of its treatment is still presented. Studies have shown that the expression of autophagic markers in the brain and peripheral inflammatory mediators are dysregulated in depression. Autophagy-related genes regulate the level of autophagy and change the inflammatory response in depression. Depression is related to several aspects of immunity. The regulation of the immune system and inflammation by autophagy may lead to the development or deterioration of mental disorders. This review highlights the role of autophagy and neuroinflammation in the pathophysiology of depression, sumaries the autophagy-targeting small moleculars, and discusses a novel therapeutic strategy based on anti-inflammatory mechanisms that target autophagy to treat the disease.

Kappa opioid receptor in nucleus accumbens regulates depressive-like behaviors following prolonged morphine withdrawal in mice

Prolonged withdrawal from opioids leads to negative emotions. Kappa opioid receptor (KOR) plays an important role in opioid addiction and affective disorders. However, the underlying mechanism of KOR in withdrawal-related depression is still lacking. We found that escitalopram treatment had a limited effect in improving depression symptoms in heroin-dependent patients. In mice, we demonstrated prolonged (4 weeks) but not acute (24 h) withdrawal from morphine induced depressive-like behaviors. The number of c-Fos positive cells and the expression of KOR in the nucleus accumbens (NAc), were significantly increased in the prolonged morphine withdrawal mice. Conditional KOR knockdown in NAc significantly improved depressive-like behaviors. Repeated but not acute treatment with the KOR antagonist norBNI improved depressive-like behaviors and reversed PSD95, synaptophysin, p-ERK, p-CREB, and BDNF in NAc. This study demonstrated the important role of striatal KOR in morphine withdrawal-related depressive-like behaviors and offered therapeutic potential for the treatment of withdrawal-related depression.

Mechanism of ERK/CREB pathway in pain and analgesia

Research has long centered on the pathophysiology of pain. The Transient Receiver Potential (TRP) protein family is well known for its function in the pathophysiology of pain, and extensive study has been done in this area. One of the significant mechanisms of pain etiology and analgesia that lacks a systematic synthesis and review is the ERK/CREB (Extracellular Signal-Regulated Kinase/CAMP Response Element Binding Protein) pathway. The ERK/CREB pathway-targeting analgesics may also cause a variety of adverse effects that call for specialized medical care. In this review, we systematically compiled the mechanism of the ERK/CREB pathway in the process of pain and analgesia, as well as the potential adverse effects on the nervous system brought on by the inhibition of the ERK/CREB pathway in analgesic drugs, and we suggested the corresponding solutions.

Microglial infiltration mediates cognitive dysfunction in rat models of hypothalamic obesity via a hypothalamic-hippocampal circuit involving the lateral hypothalamic area

This study aimed to explore the mechanism underlying cognitive dysfunction mediated by the lateral hypothalamic area (LHA) in a hypothalamic-hippocampal circuit in rats with lesion-induced hypothalamic obesity (HO). The HO model was established by electrically lesioning the hypothalamic nuclei. The open field (OP) test, Morris water maze (MWM), novel object recognition (NOR), and novel object location memory (NLM) tests were used to evaluate changes in cognition due to alterations in the hypothalamic-hippocampal circuit. Western blotting, immunohistochemical staining, and cholera toxin subunit B conjugated with Alexa Fluor 488 (CTB488) reverse tracer technology were used to determine synaptophysin (SYN), postsynaptic density protein 95 (PSD95), ionized calcium binding adaptor molecule 1 (Iba1), neuronal nuclear protein (NeuN), and Caspase3 expression levels and the hypothalamic-hippocampal circuit. In HO rats, severe obesity was associated with cognitive dysfunction after the lesion of the hypothalamus. Furthermore, neuronal apoptosis and activated microglia in the downstream of the lesion area (the LHA) induced microglial infiltration into the intact hippocampus via the LHA-hippocampal circuit, and the synapses engulfment in the hippocampus may be the underlying mechanism by which the remodeled microglial mediates memory impairments in HO rats. The HO rats exhibited microglial infiltration and synapse loss into the hippocampus from the lesioned LHA via the hypothalamic-hippocampal circuit. The underlying mechanisms of memory function may be related to the circuit.