CEBPβ regulation of endogenous IGF-1 in adult sensory neurons can be mobilized to overcome diabetes-induced deficits in bioenergetics and axonal outgrowth

Deficiency of Aging-Related Gene Chitinase-Like 4 Impairs Olfactory Epithelium Homeostasis

Mammalian olfactory epithelium (OE) undergoes consistent self-renewal throughout life. In OE homeostasis, globose basal cells (GBCs) contribute to the generation of olfactory sensory neurons (OSNs) to replace old ones. Chitinase-like 4 (Chil4), a chitinase-like protein expressed in supporting cells, plays a critical role in OE regeneration, while its role in tissue homeostasis is still elusive. Here, we found that Chil4 is upregulated in the aged OE. Deletion of Chil4 leads to a reduction in the number of GBCs and immature OSNs (iOSNs). Chil4-/- GBCs show attenuation in cell cycle progression and an aberrant expression pattern of cell-cycle-related genes such as Cdk1. Chil4 deletion causes loss of a specific subcluster of GAP43+ iOSNs expressing Cebpb, Nqo1 and low level of mature OSN (mOSN) marker Stoml3 (iOSN_CeStLNq), potentially suggesting a transitional state between immature and mature neurons. Chil4 knockout induces inflammatory activation in Iba1+ microglia (MG)-like cells in the OE. Chil4 downregulation in aged organoids reduced the number of mature sensory neurons, suggesting a necessary role of Chil4 in maintaining neuronal generation in the aged OE. Collectively, these observations reveal a previously unidentified function of Chil4, establishing the cellular mechanism underlying OE homeostasis.

Advances in research on mitochondrial dysfunction in neurodegenerative diseases

Given the high energy demand of the nervous system, mitochondrial dysfunction is a key factor in the pathogenesis of neurodegenerative diseases. Thus, a comprehensive understanding of its mechanisms and potential therapeutic targets is essential. This review discusses the roles of mitochondrial oxidative stress, mitochondrial dynamics alterations, and mtDNA damage in Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and multiple sclerosis (MS). In addition, it summarizes the contributions of novel technological approaches in detecting mitochondrial dysfunction, which assist in disease diagnosis. We also emphasize emerging therapeutic strategies and drugs aimed at enhancing mitochondrial quality control and reducing oxidative stress, thereby laying the groundwork for innovative therapeutic approaches in neurodegenerative disease treatment.

Role of Mitochondrial Dysfunction in Neuropathy

Diabetes mellitus is characterized by a state of hyperglycemia, which can lead to severe complications if left untreated or poorly managed. Diabetic peripheral neuropathy (DPN) is one common complication. This condition is characterized by damage to the nerves that supply the legs and feet as well as problems with blood vessels, the heart, or urinary tract. To alleviate pain for patients, clinicians resort to long-term treatment regimens of nerve pain medications, which are usually either anticonvulsants or antidepressants. However, little is understood about the underlying mechanisms of DPN. Many pathogenic pathways have been proposed, one of which is mitochondrial dysfunction. Mitochondrial dysfunction includes a range of possible deficiencies given the number of functions controlled by or located in mitochondria, including their core function of bioenergetics. This review focuses on mitochondrial bioenergetics, including respiration/ATP synthesis and reactive oxygen species (ROS) production, as well as calcium homeostasis and apoptosis, and their potential as targets for the effective treatment of diabetic peripheral neuropathy.

Maternal behavior promotes resilience to adolescent stress in mice through a microglia-neuron axis

Early life experience modulates resilience to stress in later life. Previous research implicated maternal care as a key mediator of behavioral responses to the adversity in adolescence, but details of molecular mechanisms remain elusive. Here, we show social stress activates transcription factor C/EBPβ in mPFC neurons of adolescent mice, which transcriptionally upregulates Dnm1l and promotes mitochondrial dysfunction, thereby conferring stress susceptibility in adolescent mice. Moreover, different maternal separation differentially regulates adolescent stress susceptibility. Mechanistically, this differential effect depends on maternal behavior-stimulated IGF-1, which inhibits neuronal C/EBPβ through mTORC1-induced C/EBPβ-LIP translation. Furthermore, we identify maternal behavior-stimulated IGF-1 is mainly released from mPFC microglia. Notably, increased maternal care under an environmental enrichment condition or maternal behavior impairment induced by repeated MPOAEsr1+ cells inhibition in dams prevents or promotes stress susceptibility via microglial-to-neuronal IGF-1-C/EBPβ-DRP1 signaling. In this work, these findings have unveiled molecular mechanisms by which maternal behavior promotes stress resilience in adolescents.

Eye on the horizon: The metabolic landscape of the RPE in aging and disease

To meet the prodigious bioenergetic demands of the photoreceptors, glucose and other nutrients must traverse the retinal pigment epithelium (RPE), a polarised monolayer of cells that lie at the interface between the outer retina and the choroid, the principal vascular layer of the eye. Recent investigations have revealed a metabolic ecosystem in the outer retina where the photoreceptors and RPE engage in a complex exchange of sugars, amino acids, and other metabolites. Perturbation of this delicate metabolic balance has been identified in the aging retina, as well as in age-related macular degeneration (AMD), the leading cause of blindness in the Western world. Also common in the aging and diseased retina are elevated levels of cytokines, oxidative stress, advanced glycation end-products, increased growth factor signalling, and biomechanical stress - all of which have been associated with metabolic dysregulation in non-retinal cell types and tissues. Herein, we outline the role of these factors in retinal homeostasis, aging, and disease. We discuss their effects on glucose, mitochondrial, lipid, and amino acid metabolism in tissues and cell types outside the retina, highlighting the signalling pathways through which they induce these changes. Lastly, we discuss promising avenues for future research investigating the roles of these pathological conditions on retinal metabolism, potentially offering novel therapeutic approaches to combat age-related retinal disease.

Restoring sweat gland function in mice using regenerative sweat gland cells derived from chemically reprogrammed human epidermal keratinocytes

The regeneration of sweat glands (SwGs) plays a pivotal role in the functional recovery of extensive skin wounds. Recent research has illuminated the possibility of reprogramming human epidermal keratinocytes (HEKs) into induced SwG cells through the ectopic expression of ectodysplasin A. However, the clinical application of this genetic manipulation approach is inherently limited. In this study, we present findings demonstrating that a combination of six compounds can effectively and speedily reprogram HEKs in culture into fully functional SwG cells. These chemically induced SwG-like cells (ciSGCs) closely resemble the morphology, phenotypes, and functional properties of human primary SwG ductal cells. Furthermore, ciSGCs can be stimulated to differentiate into mature SwG cell types in vitro. In a 3D culture system, they can also generate SwG organoids that exhibit structural and biological features akin to native SwGs. Upon transplantation into scalded mouse paw skin, ciSGCs significantly expedited cutaneous wound healing and completely restored the structural and functional aspects of the SwGs. In conclusion, the small molecule cocktail-directed SwG reprogramming offers a non-transgenic and controllable strategy for producing high-quality, clinical-grade SwG cells, showing immense potential for the treatment of burn patients.

Diminished levels of insulin-like growth factor-1 may be a risk factor for peripheral neuropathy in type 2 diabetes patients

AIMS/INTRODUCTION

To investigate risk factors for diabetic peripheral neuropathy (DPN) and to explore the connection between insulin-like growth factor-1 (IGF-1) and DPN in individuals with type 2 diabetes.

MATERIALS AND METHODS

A total of 790 patients with type 2 diabetes participated in a cross-sectional study, divided into two groups: those with DPN (DPN) and those without DPN (non-DPN). Blood samples were taken to measure IGF-1 levels and other biochemical markers. Participants underwent nerve conduction studies and quantitative sensory testing.

RESULTS

Patients with DPN exhibited significantly lower levels of IGF-1 compared with non-DPN patients (P < 0.001). IGF-1 was positively correlated with the average amplitude of both motor (P < 0.05) and sensory nerves (P < 0.05), but negatively correlated with the vibration perception threshold (P < 0.05). No significant difference was observed between IGF-1 and nerve conduction velocity (P > 0.05), or the temperature detection threshold (P > 0.05). Multivariate regression analysis identified diabetes duration, HbA1c, and the low levels of IGF-1 as independent risk factors (P < 0.001). Receiver operating characteristic analysis determined that at 8 years duration of diabetes, 8.5% (69.4 mmol/mol) HbA1c and 120 ng/mL IGF-1, the optimal cut-off points, indicated DPN (P < 0.001).

CONCLUSIONS

A reduction of IGF-1 in patients with DPN suggests a potential protective role against axon injury in large fiber nerves of type 2 diabetes patients.

Neuronal glycolysis: focus on developmental morphogenesis and localized subcellular functions

Glycolysis is a metabolic pathway that directly generates adenosine triphosphate (ATP), provides metabolic intermediates for anabolism, and supports mitochondrial oxidative phosphorylation. This review addresses recent advances in our understanding of the functions of neuronal glycolysis during the development of neuronal morphogenesis, focusing on the emergent concept that neuronal glycolysis serves local subcellular bioenergetic roles in maintaining neuronal function. The current evidence indicates that glycolysis is subcellularly targeted to specific organelles and molecular machinery to locally supply bioenergetic support for defined subcellular mechanisms underlying neuronal morphogenesis (i.e. axon extension, axon retraction and axonal transport). Thus, the concept of glycolysis as a "housekeeping" mechanism in neurons would benefit revision and future work aim to further define its subcellular functions at varied developmental stages.

C/EBPβ: A transcription factor associated with the irreversible progression of Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disorder distinguished by a swift cognitive deterioration accompanied by distinctive pathological hallmarks such as extracellular Aβ (β-amyloid) peptides, neuronal neurofibrillary tangles (NFTs), sustained neuroinflammation, and synaptic degeneration. The elevated frequency of AD cases and its proclivity to manifest at a younger age present a pressing challenge in the quest for novel therapeutic interventions. Numerous investigations have substantiated the involvement of C/EBPβ in the progression of AD pathology, thus indicating its potential as a therapeutic target for AD treatment.

AIMS

Several studies have demonstrated an elevation in the expression level of C/EBPβ among individuals afflicted with AD. Consequently, this review predominantly delves into the association between C/EBPβ expression and the pathological progression of Alzheimer's disease, elucidating its underlying molecular mechanism, and pointing out the possibility that C/EBPβ can be a new therapeutic target for AD.

METHODS

A systematic literature search was performed across multiple databases, including PubMed, Google Scholar, and so on, utilizing predetermined keywords and MeSH terms, without temporal constraints. The inclusion criteria encompassed diverse study designs, such as experimental, case-control, and cohort studies, restricted to publications in the English language, while conference abstracts and unpublished sources were excluded.

RESULTS

Overexpression of C/EBPβ exacerbates the pathological features of AD, primarily by promoting neuroinflammation and mediating the transcriptional regulation of key molecular pathways, including δ-secretase, apolipoprotein E4 (APOE4), acidic leucine-rich nuclear phosphoprotein-32A (ANP32A), transient receptor potential channel 1 (TRPC1), and Forkhead BoxO (FOXO).

DISCUSSION

The correlation between overexpression of C/EBPβ and the pathological development of AD, along with its molecular mechanisms, is evident. Investigating the pathways through which C/EBPβ regulates the development of AD reveals numerous multiple vicious cycle pathways exacerbating the pathological progression of the disease. Furthermore, the exacerbation of pathological progression due to C/EBPβ overexpression and its molecular mechanism is not limited to AD but also extends to other neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and multiple sclerosis (MS).

CONCLUSION

The overexpression of C/EBPβ accelerates the irreversible progression of AD pathophysiology. Additionally, C/EBPβ plays a crucial role in mediating multiple pathways linked to AD pathology, some of which engender vicious cycles, leading to the establishment of feedback mechanisms. To sum up, targeting C/EBPβ could hold promise as a therapeutic strategy not only for AD but also for other degenerative diseases.

The interaction between ageing and Alzheimer's disease: insights from the hallmarks of ageing

Ageing is a crucial risk factor for Alzheimer's disease (AD) and is characterised by systemic changes in both intracellular and extracellular microenvironments that affect the entire body instead of a single organ. Understanding the specific mechanisms underlying the role of ageing in disease development can facilitate the treatment of ageing-related diseases, such as AD. Signs of brain ageing have been observed in both AD patients and animal models. Alleviating the pathological changes caused by brain ageing can dramatically ameliorate the amyloid beta- and tau-induced neuropathological and memory impairments, indicating that ageing plays a crucial role in the pathophysiological process of AD. In this review, we summarize the impact of several age-related factors on AD and propose that preventing pathological changes caused by brain ageing is a promising strategy for improving cognitive health.

IGF/IGF-1R signal pathway in pain: a promising therapeutic target

Pain, one of the most important problems in the field of medicine and public health, has great research significance. Opioids are still the main drugs to relieve pain now. However, its application is limited due to its obvious side effects. Therefore, it is urgent to develop new drugs to relieve pain. Multiple studies have found that IGF/IGF-1R pathway plays an important role in the occurrence and development of pain. The regulation of IGF/IGF-1R pathway has obvious effect on pain. This review summarized and discussed the therapeutic potential of IGF/IGF-1R signal pathway for pain. It also summarized that IGF/IGF-1R regulates pain by acting on neuronal excitability, neuroinflammation, glial cells, apoptosis, etc. However, its mechanisms of occurrence and development in pain still need further study in the future. In conclusion, although more deep researches are needed, these studies indicate that IGF/IGF-1R signal pathway is a promising therapeutic target for pain.

CEBP-β and PLK1 as Potential Mediators of the Breast Cancer/Obesity Crosstalk: In Vitro and In Silico Analyses

Over the last two decades, obesity has reached pandemic proportions in several countries, and expanding evidence is showing its contribution to several types of malignancies, including breast cancer (BC). The conditioned medium (CM) from mature adipocytes contains a complex of secretes that may mimic the obesity condition in studies on BC cell lines conducted in vitro. Here, we report a transcriptomic analysis on MCF-7 BC cells exposed to adipocyte-derived CM and focus on the predictive functional relevance that CM-affected pathways/processes and related biomarkers (BMs) may have in BC response to obesity. CM was demonstrated to increase cell proliferation, motility and invasion as well as broadly alter the transcript profiles of MCF-7 cells by significantly modulating 364 genes. Bioinformatic functional analyses unraveled the presence of five highly relevant central hubs in the direct interaction networks (DIN), and Kaplan-Meier analysis sorted the CCAAT/enhancer binding protein beta (CEBP-β) and serine/threonine-protein kinase PLK1 (PLK1) as clinically significant biomarkers in BC. Indeed, CEBP-β and PLK1 negatively correlated with BC overall survival and were up-regulated by adipocyte-derived CM. In addition to their known involvement in cell proliferation and tumor progression, our work suggests them as a possible "deus ex machina" in BC response to fat tissue humoral products in obese women.

Transcriptional Profiling of Rat Prefrontal Cortex after Acute Inescapable Footshock Stress

Stress is a primary risk factor for psychiatric disorders such as Major Depressive Disorder (MDD) and Post Traumatic Stress Disorder (PTSD). The response to stress involves the regulation of transcriptional programs, which is supposed to play a role in coping with stress. To evaluate transcriptional processes implemented after exposure to unavoidable traumatic stress, we applied microarray expression analysis to the PFC of rats exposed to acute footshock (FS) stress that were sacrificed immediately after the 40 min session or 2 h or 24 h after. While no substantial changes were observed at the single gene level immediately after the stress session, gene set enrichment analysis showed alterations in neuronal pathways associated with glia development, glia-neuron networking, and synaptic function. Furthermore, we found alterations in the expression of gene sets regulated by specific transcription factors that could represent master regulators of the acute stress response. Of note, these pathways and transcriptional programs are activated during the early stress response (immediately after FS) and are already turned off after 2 h-while at 24 h, the transcriptional profile is largely unaffected. Overall, our analysis provided a transcriptional landscape of the early changes triggered by acute unavoidable FS stress in the PFC of rats, suggesting that the transcriptional wave is fast and mild, but probably enough to activate a cellular response to acute stress.

C/EBPβ Regulates TFAM Expression, Mitochondrial Function and Autophagy in Cellular Models of Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disorder that results from the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Since there are only symptomatic treatments available, new cellular and molecular targets involved in the onset and progression of this disease are needed to develop effective treatments. CCAAT/Enhancer Binding Protein β (C/EBPβ) transcription factor levels are altered in patients with a variety of neurodegenerative diseases, suggesting that it may be a good therapeutic target for the treatment of PD. A list of genes involved in PD that can be regulated by C/EBPβ was generated by the combination of genetic and in silico data, the mitochondrial transcription factor A (TFAM) being among them. In this paper, we observed that C/EBPβ overexpression increased TFAM promoter activity. However, downregulation of C/EBPβ in different PD/neuroinflammation cellular models produced an increase in TFAM levels, together with other mitochondrial markers. This led us to propose an accumulation of non-functional mitochondria possibly due to the alteration of their autophagic degradation in the absence of C/EBPβ. Then, we concluded that C/EBPβ is not only involved in harmful processes occurring in PD, such as inflammation, but is also implicated in mitochondrial function and autophagy in PD-like conditions.

Pathogenesis of Dementia

According to Alzheimer's Disease International, 55 million people worldwide are living with dementia. Dementia is a disorder that manifests as a set of related symptoms, which usually result from the brain being damaged by injury or disease. The symptoms involve progressive impairments in memory, thinking, and behavior, usually accompanied by emotional problems, difficulties with language, and decreased motivation. The most common variant of dementia is Alzheimer's disease with symptoms dominated by cognitive disorders, particularly memory loss, impaired personality, and judgmental disorders. So far, all attempts to treat dementias by removing their symptoms rather than their causes have failed. Therefore, in the presented narrative review, I will attempt to explain the etiology of dementia and Alzheimer's disease from the perspective of energy and cognitive metabolism dysfunction in an aging brain. I hope that this perspective, though perhaps too simplified, will bring us closer to the essence of aging-related neurodegenerative disorders and will soon allow us to develop new preventive/therapeutic strategies in our struggle with dementia, Alzheimer's disease, and Parkinson's disease.

Roles of traditional chinese medicine regulating neuroendocrinology on AD treatment

The incidence of sporadic Alzheimer's disease (AD) is increasing in recent years. Studies have shown that in addition to some genetic abnormalities, the majority of AD patients has a history of long-term exposure to risk factors. Neuroendocrine related risk factors have been proved to be strongly associated with AD. Long-term hormone disorder can have a direct detrimental effect on the brain by producing an AD-like pathology and result in cognitive decline by impairing neuronal metabolism, plasticity and survival. Traditional Chinese Medicine(TCM) may regulate the complex process of endocrine disorders, and improve metabolic abnormalities, as well as the resulting neuroinflammation and oxidative damage through a variety of pathways. TCM has unique therapeutic advantages in treating early intervention of AD-related neuroendocrine disorders and preventing cognitive decline. This paper reviewed the relationship between neuroendocrine and AD as well as the related TCM treatment and its mechanism. The advantages of TCM intervention on endocrine disorders and some pending problems was also discussed, and new insights for TCM treatment of dementia in the future was provided.