Aging is a major risk factor for respiratory diseases, with the respiratory system demonstrating a particular vulnerability to age-related decline. This review explores the intersection between aging biology and respiratory pathophysiology, focusing on three interconnected hallmarks: cellular senescence, inflammaging, and immunosenescence. Senescent cells accumulate in aging lungs, releasing a senescence-associated secretory phenotype (SASP) that perpetuates chronic inflammation and tissue dysfunction. Natural Senotherapeutics, compounds that target senescent cells or modulate their effects, offer promising strategies to address these fundamental mechanisms. We examined the latest findings on key natural compounds (rapamycin, berberine, resveratrol, pterostilbene, quercetin, EGCG, fisetin, apigenin and curcumin) that demonstrate senomorphic and/or senolytic properties in respiratory contexts. These compounds function through diverse but overlapping molecular pathways, mainly modulating inflammation, immune dysfunction and oxidative stress. Preclinical evidence consistently supports their potential in models of chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), acute respiratory distress syndrome (ARDS), and respiratory infections, although their clinical translation remains limited. The challenges include bioavailability, optimal dosing regimens, and delivery methods. As global demographics shift toward an aging population, developing interventions that target fundamental aging mechanisms in the respiratory system is becoming increasingly urgent. Natural senotherapeutics may offer a paradigm shift in maintaining respiratory health in older adults, with potentially fewer adverse effects than synthetic alternatives.

The understanding of neurodegenerative diseases is evolving toward a systemic view, highlighting the connection between liver dysfunction and brain impairment, where metabolism and inflammation play central roles. Licochalcone A (LCA), has demonstrated antidiabetic and anti-inflammatory effects. This study aimed to evaluate its neuroprotective effects under metabolic syndrome conditions. For this purpose, male C57BL/6J mice were fed either with control (CT) or high-fat diet (HFD) from weaning. At eight months, animals received intraperitoneal LCA (15 mg/kg/day) or saline three times per week for four weeks. The resulting groups were CT Saline, HFD Saline, and HFD LCA. Cognitive and metabolic alterations were assessed through behavioral tests and glucose/insulin tolerance assays. Peripheral and/or central markers of metabolism, amyloid burden, inflammation, and synapsis were analyzed using histological staining, immunohistochemistry, Golgi staining, Western blot, ELISA, and RT-PCR. The results demonstrated that LCA administration improved metabolic outcomes by reducing body and liver weight, enhancing glucose tolerance, and improving liver histology. These effects were associated with modulation of insulin signaling pathways, including PTP1B inhibition and AKT activation in the liver and the hippocampus. LCA also reduced HFD-induced Aβ accumulation, which was accompanied by increased LRP1 expression, and attenuated the expression of inflammatory related markers, such as TLR4 and glial activation. Moreover, these improvements were associated with increased levels of synaptic proteins (BDNF, PSD95, DBN1), and synaptic plasticity markers (P-CREB and P-LIMK1), along with preservation of dendritic spine density and improved memory performance. In conclusion, these findings support LCA as a promising candidate for treating HFD-induced neurodegenerative conditions, acting through modulation of metabolic and inflammatory pathways across the liver-brain axis.

Alzheimer's disease (AD) is a complex neurodegenerative disorder. Current therapeutic approaches targeting a single pathway have shown limited efficacy, highlighting the need for multi-target interventions. Licochalcone A (LCA), a chalcone of licorice root, has demonstrated anti-inflammatory and antidiabetic properties. However, its potential neuroprotective mechanisms in AD remain unclear. The present study aims to elucidate the beneficial effect of LCA against cognitive decline in an AD mouse model. For this purpose, five-month-old APPswe/PS1dE9 (APP/PS1) mice received intraperitoneal LCA (15 mg·kg−1·day−1) treatment for 4 weeks. Afterwards, cognitive function was assessed using Morris water maze (MWM) and Novel object recognition test (NORT). Metabolism was evaluated through glucose and insulin tolerance tests. Biochemical markers of synapses, neurogenesis, metabolism, Amyloid-β (Aβ) burden and neuroinflammation were analyzed using immunohistochemistry, Thioflavin-S staining, Golgi staining, Western blot, ELISA and RT-PCR. The results demonstrated that LCA significantly improved long-term memory in APP/PS1 mice, through MWM and NORT, accompanied by an increased dendritic spine density, upregulated PSD95 and spinophilin levels, and enhanced Ki67-positive cells in the hippocampus. Moreover, LCA treatment ameliorated glucose tolerance and initial insulin response while increasing Insr expression and GLUT1 protein levels. Furthermore, LCA-treated APP/PS1 mice showed reduced plaque burden and Aβ42 levels. Alongside, LCA demonstrated its anti-inflammatory effect by reducing glial reactivity, and Trem2 expression. In conclusion, the present study demonstrates the multiple therapeutic effects of LCA in APP/PS1 mice by simultaneously modulating glucose metabolism, reducing Aβ accumulation and attenuating neuroinflammation, ultimately enhancing cognitive resilience. These findings establish LCA as a promising multi-target compound for AD treatment.

Colistin, a last-resort antibiotic against multidrug-resistant Gram-negative infections, is limited by severe nephrotoxicity and neurotoxicity driven by oxidative stress and mitochondrial dysfunction. Effective neuroprotective strategies, particularly targeting the central nervous system, remain scarce. This study aimed to identify a natural compound capable of mitigating colistin-induced toxicity through an integrated in vitro and in vivo analysis. Five bioactive molecules with antioxidant and mitochondrial-stabilizing properties were screened in primary neuronal cultures exposed to colistin. Among them, epigallocatechin-3-gallate (EGCG) emerged as the most effective candidate. Its protective actions were then evaluated in a mouse model of colistin toxicity using molecular, histopathological, and behavioral assessment. EGCG pretreatment prevented colistin-induced weight loss, renal tubular apoptosis, and neuromotor impairment while preserving muscle strength. In the central nervous system, EGCG maintained dendritic spine density, reduced caspase-3 activity, and attenuated astrogliosis. Mechanistically, its benefits were associated with reduced reactive oxygen species levels and preserved mitochondrial membrane potential in vitro. Behavioral analysis further supported these findings, revealing improvements in recognition memory and reductions in anxiety- and depressive-like behaviors. Overall, this study provides comprehensive evidence that EGCG confers broad neuro- and nephroprotective effects against colistin toxicity, highlighting its potential as a safe adjuvant to enhance the therapeutic window of polymyxins.

The rise of antimicrobial resistance has made necessary the increase of the antibacterial arsenal against multidrug-resistant bacteria. In this context, colistin has re-emerged as a first-line antibiotic in critical situations despite its nephro- and neuro- toxicity at peripheral level. However, the mechanism underlying its toxicity remains unknown, particularly in relation to the central nervous system (CNS). Therefore, this study aimed to characterize the molecular mechanisms underlying colistin-induced neurotoxicity in the CNS through a combination of in vitro and in vivo molecular studies along with several in vivo behavioral tests. Following colistin treatment, mice exhibited a significant reduction in body weight together with renal impairment, and locomotor dysfunction. Moreover, our results demonstrated that colistin disrupted the blood-brain barrier, inducing astrogliosis, and triggering apoptosis-related processes probably through the accumulation of reactive oxygen species (ROS) and mitochondrial dysfunction. Further analysis on mice and primary neuronal cultures revealed that colistin administration altered neuronal plasticity by reducing the number of immature neurons in adult neurogenesis and altering the synaptic function through a reduction of the post-synaptic protein PSD95. All these alterations together finally lead to cognitive impairment and depression-like symptoms in mice. These findings provide novel insights into the mechanisms of colistin-induced neurotoxicity in the CNS, highlighting the need for careful monitoring of cognitive function in patients undergoing colistin treatment.

Inflammation plays a key role in the development of neurodegenerative disorders that are currently incurable. Licochalcone A (LCA) has been described as an emerging anti-inflammatory drug with multiple therapeutical properties that could potentially prevent neurodegeneration. However, its neuroprotective mechanism remains unclear. Here, we investigated if LCA prevents cognitive decline induced by Lipopolysaccharide (LPS) and elucidated its potential benefits. For that, 8-week-old C57BL6/J male mice were intraperitonially (i.p.) treated with saline solution or LCA (15 mg/kg/day, 3 times per week) for two weeks. The last day, a single i.p injection of LPS (1 mg/kg) or saline solution was administered 24 h before sacrifice. The results revealed a significant reduction in mRNA expression in genes involved in oxidative stress (Sod1, Cat, Pkm, Pdha1, Ndyfv1, Uqcrb1, Cycs and Cox4i1), metabolism (Slc2a1, Slc2a2, Prkaa1 and Gsk3b) and synapsis (Bdnf, Nrxn3 and Nlgn2) in LPS group compared to saline. These findings were linked to memory impairment and depressive-like behavior observed in this group. Interestingly, LCA protected against LPS alterations through its anti-inflammatory effect, reducing gliosis and regulating M1/M2 markers. Moreover, LCA-treated animals showed a significant improvement of antioxidant mechanisms, such as citrate synthase activity and SOD2. Additionally, LCA demonstrated protection against metabolic disturbances, downregulating GLUT4 and P-AKT, and enhanced the expression of synaptic-related proteins (P-CREB, BDNF, PSD95, DBN1 and NLG3), leading all together to dendritic spine preservation. In conclusion, our results demonstrate that LCA treatment prevents LPS-induced cognitive decline by reducing inflammation, enhancing the antioxidant response, protecting against metabolic disruptions and improving synapsis related mechanisms.

Mitochondrial dynamics and trafficking are essential to provide the energy required for neurotransmission and neural activity. We investigated how G protein–coupled receptors (GPCRs) and G proteins control mitochondrial dynamics and trafficking. The activation of Gα q inhibited mitochondrial trafficking in neurons through a mechanism that was independent of the canonical downstream PLCβ pathway. Mitoproteome analysis revealed that Gα q interacted with the Eutherian-specific mitochondrial protein armadillo repeat–containing X-linked protein 3 (Alex3) and the Miro1/Trak2 complex, which acts as an adaptor for motor proteins involved in mitochondrial trafficking along dendrites and axons. By generating a CNS-specific Alex3 knockout mouse line, we demonstrated that Alex3 was required for the effects of Gα q on mitochondrial trafficking and dendritic growth in neurons. Alex3-deficient mice had altered amounts of ER stress response proteins, increased neuronal death, motor neuron loss, and severe motor deficits. These data revealed a mammalian-specific Alex3/Gα q mitochondrial complex, which enables control of mitochondrial trafficking and neuronal death by GPCRs.

C-Jun-N-terminal-kinases (JNKs), members of the mitogen-activated-protein-kinase family, are significantly linked with neurological and neurodegenerative pathologies and cancer progression. However, JNKs serve key roles under physiological conditions, particularly within the central-nervous-system (CNS), where they are critical in governing neural proliferation and differentiation during both embryogenesis and adult stages. These processes control the development of CNS, avoiding neurodevelopment disorders. JNK are key to maintain the proper activity of neural-stem-cells (NSC) and neural-progenitors (NPC) that exist in adults, which keep the convenient brain plasticity and homeostasis. This review underscores how the interaction of JNK with upstream and downstream molecules acts as a regulatory mechanism to manage the self-renewal capacity and differentiation of NSC/NPC during CNS development and in adult neurogenic niches. Evidence suggests that JNK is reliant on non-canonical Wnt components, Fbw7-ubiquitin-ligase, and WDR62-scaffold-protein, regulating substrates such as transcription factors and cytoskeletal proteins. Therefore, understanding which pathways and molecules interact with JNK will bring knowledge on how JNK activation orchestrates neuronal processes that occur in CNS development and brain disorders.

Air pollution, a growing concern for public health, has been linked to various respiratory and cardiovascular diseases. Emerging evidence also suggests a link between exposure to air pollutants and neurodegenerative diseases, particularly Alzheimer’s disease (AD). This review explores the composition and sources of air pollutants, including particulate matter, gases, persistent organic pollutants, and heavy metals. The pathophysiology of AD is briefly discussed, highlighting the role of beta-amyloid plaques, neurofibrillary tangles, and genetic factors. This article also examines how air pollutants reach the brain and exert their detrimental effects, delving into the neurotoxicity of air pollutants. The molecular mechanisms linking air pollution to neurodegeneration are explored in detail, focusing on oxidative stress, neuroinflammation, and protein aggregation. Preclinical studies, including in vitro experiments and animal models, provide evidence for the direct effects of pollutants on neuronal cells, glial cells, and the blood–brain barrier. Epidemiological studies have reported associations between exposure to air pollution and an increased risk of AD and cognitive decline. The growing body of evidence supporting air pollution as a modifiable risk factor for AD underscores the importance of considering environmental factors in the etiology and progression of neurodegenerative diseases, in the face of worsening global air quality.

Licochalcone A (Lico-A) is a flavonoid compound derived from the root of the Glycyrrhiza species, a plant commonly used in traditional Chinese medicine. While the Glycyrrhiza species has shown promise in treating various diseases such as cancer, obesity, and skin diseases due to its active compounds, the investigation of Licochalcone A's effects on the central nervous system and its potential application in Alzheimer's disease (AD) treatment have garnered significant interest. Studies have reported the neuroprotective effects of Lico-A, suggesting its potential as a multitarget compound. Lico-A acts as a PTP1B inhibitor, enhancing cognitive activity through the BDNF-TrkB pathway and exhibiting inhibitory effects on microglia activation, which enables mitigation of neuroinflammation. Moreover, Lico-A inhibits c-Jun N-terminal kinase 1, a key enzyme involved in tau phosphorylation, and modulates the brain insulin receptor, which plays a role in cognitive processes. Lico-A also acts as an acetylcholinesterase inhibitor, leading to increased levels of the neurotransmitter acetylcholine (Ach) in the brain. This mechanism enhances cognitive capacity in individuals with AD. Finally, Lico-A has shown the ability to reduce amyloid plaques, a hallmark of AD, and exhibits antioxidant properties by activating the nuclear factor erythroid 2-related factor 2 (Nrf2), a key regulator of antioxidant defense mechanisms. In the present review, we discuss the available findings analyzing the potential of Lico-A as a neuroprotective agent. Continued research on Lico-A holds promise for the development of novel treatments for cognitive disorders and neurodegenerative diseases, including AD. Further investigations into its multitarget action and elucidation of underlying mechanisms will contribute to our understanding of its therapeutic potential.

Background Alzheimer’s disease (AD) is characterized by a polyetiological origin. Despite the global burden of AD and the advances made in AD drug research and development, the cure of the disease remains elusive, since any developed drug has demonstrated effectiveness to cure AD. Strikingly, an increasing number of studies indicate a linkage between AD and type 2 diabetes mellitus (T2DM), as both diseases share some common pathophysiological features. In fact, β-secretase (BACE1) and acetylcholinesterase (AChE), two enzymes involved in both conditions, have been considered promising targets for both pathologies. In this regard, due to the multifactorial origin of these diseases, current research efforts are focusing on the development of multi-target drugs as a very promising option to derive effective treatments for both conditions. In the present study, we evaluated the effect of rhein-huprine hybrid (RHE-HUP), a synthesized BACE1 and AChE inhibitor, both considered key factors not only in AD but also in metabolic pathologies. Thus, the aim of this study is to evaluate the effects of this compound in APP/PS1 female mice, a well-established familial AD mouse model, challenged by high-fat diet (HFD) consumption to concomitantly simulate a T2DM-like condition. Results Intraperitoneal treatment with RHE-HUP in APP/PS1 mice for 4 weeks reduced the main hallmarks of AD, including Tau hyperphosphorylation, Aβ 42 peptide levels and plaque formation. Moreover, we found a decreased inflammatory response together with an increase in different synaptic proteins, such as drebrin 1 (DBN1) or synaptophysin, and in neurotrophic factors, especially in BDNF levels, correlated with a recovery in the number of dendritic spines, which resulted in memory improvement. Notably, the improvement observed in this model can be attributed directly to a protein regulation at central level, since no peripheral modification of those alterations induced by HFD consumption was observed. Conclusions Our results suggest that RHE-HUP could be a new candidate for the treatment of AD, even for individuals with high risk due to peripheral metabolic disturbances, given its multi-target profile which allows for the improvement of some of the most important hallmarks of the disease.

Peroxisome proliferator-activated receptor β/δ (PPARβ/δ), the most PPAR abundant isotype in the central nervous system, is involved in microglial homeostasis and metabolism, whose disturbances have been demonstrated to play a key role in memory impairment. Although PPARβ/δ function is well-established in metabolism, its contribution to neuronal and specifically memory process is underexplored. Therefore, the aim of the study is to determine the role of PPARβ/δ in the neuropathological pathways involved in memory impairment and as to whether a risk factor implicated in memory loss such as obesity modulates neuropathological markers. To carry out this study, 6-month-old total knock-out for the Ppard gene male mice with C57BL/6X129/SV background (PPARβ/δ-/-) and wild-type (WT) littermates with the same genetic background were used. Animals were fed, after the weaning (at 21 days old), and throughout their growth, either conventional chow (CT) or a palmitic acid-enriched diet (HFD). Thus, four groups were defined: WT CT, WT HFD, PPARβ/δ-/- CT, and PPARβ/δ-/- HFD. Before sacrifice, novel object recognition test (NORT) and glucose and insulin tolerance tests were performed. After that, animals were sacrificed by intracardiac perfusion or cervical dislocation. Different techniques, such as GolgiStain kit or immunofluorescence, were used to evaluate the role of PPARβ/δ in memory dysfunction. Our results showed a decrease in dendritic spine density and synaptic markers in PPARβ/δ-/- mice, which were corroborated in the NORT. Likewise, our study demonstrated that the lack of PPARβ/δ receptor enhances gliosis in the hippocampus, contributing to astrocyte and microglial activation and to the increase in neuroinflammatory biomarkers. Additionally, alterations in the hippocampal insulin receptor pathway were found. Interestingly, while some of the disturbances caused by the lack of PPARβ/δ were not affected by feeding the HFD, others were exacerbated or required the combination of both factors. Taken together, the loss of PPARβ/δ-/- affects neuronal and synaptic structure, contributing to memory dysfunction, and they also present this receptor as a possible new target for the treatment of memory impairment.

The increases in population ageing and growth are leading to a boosting in the number of people living with dementia, Alzheimer’s disease (AD) being the most common cause. In spite of decades of intensive research, no cure for AD has been found yet. However, some treatments that may change disease progression and help control symptoms have been proposed. Beyond the classical hypotheses of AD etiopathogenesis, i.e., amyloid beta peptide (Aβ) accumulation and tau hyperphosphorylation, a trend in attributing a key role to other molecular mechanisms is prompting the study of different therapeutic targets. Hence, drugs designed to modulate inflammation, insulin resistance, synapses, neurogenesis, cardiovascular factors and dysbiosis are shaping a new horizon in AD treatment. Within this frame, an increase in the number of candidate drugs for disease modification treatments is expected, as well as a focus on potential combinatory multidrug strategies.The present review summarizes the latest advances in drugs targeting Aβ and tau as major contributors to AD pathophysiology. In addition, it introduces the most important drugs in clinical studies targeting alternative mechanisms thought to be involved in AD’s neurodegenerative process.

Abstract Background and aim The appearance of alterations in normal metabolic activity has been increasingly considered a risk factor for the development of sporadic and late-onset neurodegenerative diseases. In this report, we induced chronic metabolic stress by feeding of a high-fat diet (HFD) in order to study its consequences in cognition. We also studied the effects of a loss of function of isoforms 1 and 3 of the c-Jun N-terminal Kinases (JNK), stress and cell death response elements. Methods Animals were fed either with conventional chow or with HFD, from their weaning until their sacrifice at 9 months. Before sacrifice, body weight, intraperitoneal glucose and insulin tolerance test (IP-GTT and IP‑ITT) were performed to evaluate peripheral biometrics. Additionally, cognitive behavioral tests and analysis of spine density were performed to assess cognitive function. Molecular studies were carried out to confirm the effects of metabolic stressors in the hippocampus relative to cognitive loss. Results Our studies demonstrated that HFD in Jnk3−/− lead to synergetic responses. Loss of function of JNK3 led to increased body weight, especially when exposed to an HFD and they had significantly decreased response to insulin. These mice also showed increased stress in the endoplasmic reticulum and diminished cognitive capacity. However, loss of function of JNK1 promoted normal or heightened energetic metabolism and preserved cognitive function even when chronically metabolically stressed. Conclusions Downregulation of JNK3 does not seem to be a suitable target for the modulation of energetic-cognitive dysregulations while loss of function of JNK1 seems to promote a good metabolic-cognitive profile, just like resistance to the negative effects of chronic feeding with HFD.