Investigation the mechanism of iron overload-induced colonic inflammation following ferric citrate exposure.

Iron overload occurs due to excessive iron intake compared to the body's demand, leading to iron deposition and impairment of multiple organ functions. Our previous study demonstrated that chronic oral administration of ferric citrate (FC) caused colonic inflammatory injury. However, the precise mechanism underlying this inflammatory response remains unclear. The current study aims to investigate the mechanism by which iron overload induced by FC exposure leads to colonic inflammation. To accomplish this, mice were orally exposed to three different concentrations of FC (71 mg/kg/bw (L), 143 mg/kg/bw (M) and 286 mg/kg/bw (H)) for continuous 16 weeks, with the control group receiving ultrapure water (C). Exposure to FC caused disturbances in the excretory system, altered colonic flora alpha diversity, and enriched pathogenic bacteria, such as Mucispirillum, Helicobacter, Desulfovibrio, and Shigella. These changes led to structural disorders of the colonic flora and an inflammatory response phenotype characterized by inflammatory cells infiltration, atrophy of intestinal glands, and irregular thickening of the intestinal wall. Mechanistic studies revealed that FC-exposure activated the NF-κB signaling pathway by up-regulating TLR4, MyD88, and NF-κB mRNA levels and protein expression. This activation resulted in increased production of pro-inflammatory cytokines, further contributing to the colonic inflammation. Additionally, in vitro experiments in SW480 cells confirmed the activation of NF-κB signaling pathway by FC exposure, consistent with the in vivo findings. The significance of this study lies in its elucidation of the mechanism by which iron overload caused by FC exposure leads to colonic inflammation. By identifying the role of pathogenic bacteria and the NF-κB signaling pathway, this study could potentially offer a crucial theoretical foundation for the research on iron overload, as well as provide valuable insights for clinical iron supplementation.

The contribution of initial concussive forces and resulting acrolein surge to ß-amyloid accumulation and functional alterations in neuronal networks using a TBI-on-a-chip model.

Trauma-induced Alzheimer's disease (AD) is rapidly emerging as a major consequence of traumatic brain injuries (TBI), with devastating social and economic impacts. Unfortunately, few treatment options are currently available due to a limited understanding of the underlying mechanisms. A clinically-relevant, in vitro experimental model that emulates in vivo scenarios with high levels of spatial and temporal resolution is critical for demystifying the pathways of post-TBI AD. Using a unique, recently established "TBI-on-a-chip" system with murine cortical networks, we demonstrate the correlative elevation of oxidative stress (acrolein), inflammation (TNF-α), and Aß42 aggregation, with concomitant reduction of neuronal network electrical activity post-concussive impact. These findings confirm that TBI-on-a-chip could provide a novel paradigm to supplement in vivo studies of trauma, while simultaneously validating the interaction of these alleged, key-pathological factors in post-TBI AD development. Specifically, we have shown that acrolein, acting as a diffusive factor of secondary injury, is both critical and sufficient in promoting inflammation (TNF-α) and Aß42 aggregation, two known contributors of AD pathogenesis. Furthermore, using a cell-free preparation with TBI-on-a-chip, we have confirmed that both force and acrolein can independently and directly stimulate the aggregation of purified Aß42, highlighting the key capabilities of primary and secondary injury mechanisms towards inducing Aß42 aggregation, independently and synergistically. In addition to morphological and biochemical assessment, we also demonstrate parallel monitoring of neuronal network activity, further validating the chief pathological role of acrolein in not only inflicting biochemical abnormalities, but also functional deficits in neuronal networks. In conclusion, through this line of investigations, we have shown that by recapitulating clinically-relevant events, the TBI-on-a-chip device is capable of quantitatively characterizing parallel force-dependent increases in oxidative stress, inflammation, protein aggregation, and network activity, offering a unique platform for mechanistic investigations of post-TBI AD, and trauma-induced neuronal injury in general. It is expected that this model could provide crucial insights into pathological mechanisms which will be critical in developing novel, effective diagnostics and treatment strategies that significantly benefit TBI victims.

Ferric citrate-induced colonic mucosal damage associated with oxidative stress, inflammation responses, apoptosis, and the changes of gut microbial composition.

Ferric citrate (FC) has been used as an iron fortifier and nutritional supplement, which is reported to induce colitis in rats, however the underlying mechanism remains to be elucidated. We performed a 16-week study of FC in male healthy C57BL/6 mice (nine-month-old) with oral administration of Ctr (0.9 % NaCl), 1.25 % FC (71 mg/kg/bw), 2.5 % FC (143 mg/kg/bw) and 5 % FC (286 mg/kg/bw). FC-exposure resulted in colon iron accumulation, histological alteration and reduce antioxidant enzyme activities, such as glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and total antioxidant capacity (T-AOC), together with enhanced lipid peroxidation level, including malondialdehyde (MDA) level and 4-Hydroxynonenal (4-HNE) protein expression. Exposure to FC was associated with upregulated levels of the interleukin (IL)- 6, IL-1ß, IL-18, IL-8 and tumor necrosis factor α (TNF-α), while down-regulated levels of IL-4 and IL-10. Exposure to FC was positively associated with the mRNA and protein expressions of cysteine-aspartic proteases (Caspase)- 9, Caspase-3, Bcl-2-associated X protein (Bax), while negatively associated with B-cell lymphoma 2 (Bcl2) in mitochondrial apoptosis signaling pathway. FC-exposure changed the diversity and composition of gut microbes. Additionally, the serum lipopolysaccharide (LPS) contents increased in FC-exposed groups when compared with the control group, while the expression of colonic tight junction proteins (TJPs), such as Claudin-1 and Occludin were decreased. These findings indicate that the colonic mucosal injury induced by FC-exposure are associated with oxidative stress generation, inflammation response and cell apoptosis, as well as the changes in gut microbes diversity and composition.

Andrographolide inhibits murine embryonic neuronal development through PFKFB3-mediated glycolytic pathway.

Dysregulation of neuronal development may cause neurodevelopmental disorders. However, how to regulate embryonic neuronal development and whether this regulation can be medical interrupted are largely unknown. This study aimed to investigate whether and how andrographolide (ANP) regulates embryonic neuronal development. The pregnant mice at embryonic day 10.5 (E10.5) were administrated with ANP, and the embryonic brains were harvested at E17.5 or E18.5. Immunofluorescence (IF), Immunohistochemistry (IHC) performed to determine whether ANP is critical in regulating neuronal development. Real-time quantitative PCR, western blotting, cell counting kit-8 assay, Flow Cytometry assay, Boyden Chamber Migration assay carried out to evaluate whether ANP regulates neuronal proliferation and migration. Protein-protein interaction, CO-immunoprecipitation and IF staining carried out to evaluate whether ANP regulates the interaction between PFKFB3, NeuN and TBR1. Knockdown or overexpression of PFKFB3 by adenovirus infection were used to determine whether ANP inhibits neuronal development through PFKFB3 mediated glycolytic pathway. Our data indicated that ANP inhibited the maturation of embryonic neurons characterized by suppressing neuronal proliferation and migration. ANP regulated the interaction between PFKFB3, NeuN, and TBR1. Knockdown of PFKFB3 aggravated ANP mediated inhibition of neuronal proliferation and migration, while overexpression of PFKFB3 attenuated ANP mediated neuronal developmental suppression. In summary, ANP suppressed the expression of PFKFB3, and interrupted the interaction between TRB1 and NeuN, resulting in suppressing neuronal proliferation, migration and maturation and eventually inhibiting murine embryonic neuronal development.

Polyphyllin I Promotes Autophagic Cell Death and Apoptosis of Colon Cancer Cells via the ROS-Inhibited AKT/mTOR Pathway.

Colon cancer is a common malignant tumor of the digestive tract, and it is considered among the biggest killers. Scientific and reasonable treatments can effectively improve the survival rate of patients if performed in the early stages. Polyphyllin I (PPI), a pennogenyl saponin isolated from Paris polyphylla var. yunnanensis, has exhibited strong anti-cancer activities in previous studies. Here, we report that PPI exhibits a cytotoxic effect on colon cancer cells. PPI suppressed cell viability and induced autophagic cell death in SW480 cells after 12 and 24 h, with the IC50 values 4.9 ± 0.1 µmol/L and 3.5 ± 0.2 µmol/L, respectively. Furthermore, we found PPI induced time-concentration-dependent autophagy and apoptosis in SW480 cells. In addition, down-regulated AKT/mTOR activity was found in PPI-treated SW480 cells. Increased levels of ROS might link to autophagy and apoptosis because reducing the level of ROS by antioxidant N-acetylcysteine (NAC) treatment mitigated PPI-induced autophagy and apoptosis. Although we did not know the molecular mechanism of how PPI induced ROS production, this is the first study to show that PPI induces ROS production and down-regulates the AKT/mTOR pathway, which subsequently promotes the autophagic cell death and apoptosis of colon cancer cells. This present study reports PPI as a potential therapeutic agent for colon cancer and reveals its underlying mechanisms of action.

Critical role of mitochondrial aldehyde dehydrogenase 2 in acrolein sequestering in rat spinal cord injury.

Lipid peroxidation-derived aldehydes, such as acrolein, the most reactive aldehyde, have emerged as key culprits in sustaining post-spinal cord injury (SCI) secondary pathologies leading to functional loss. Strong evidence suggests that mitochondrial aldehyde dehydrogenase-2 (ALDH2), a key oxidoreductase and powerful endogenous anti-aldehyde machinery, is likely important for protecting neurons from aldehydes-mediated degeneration. Using a rat model of spinal cord contusion injury and recently discovered ALDH2 activator (Alda-1), we planned to validate the aldehyde-clearing and neuroprotective role of ALDH2. Over an acute 2 day period post injury, we found that ALDH2 expression was significantly lowered post-SCI, but not so in rats given Alda-1. This lower enzymatic expression may be linked to heightened acrolein-ALDH2 adduction, which was revealed in co-immunoprecipitation experiments. We have also found that administration of Alda-1 to SCI rats significantly lowered acrolein in the spinal cord, and reduced cyst pathology. In addition, Alda-1 treatment also resulted in significant improvement of motor function and attenuated post-SCI mechanical hypersensitivity up to 28 days post-SCI. Finally, ALDH2 was found to play a critical role in in vitro protection of PC12 cells from acrolein exposure. It is expected that the outcome of this study will broaden and enhance anti-aldehyde strategies in combating post-SCI neurodegeneration and potentially bring treatment to millions of SCI victims. All animal work was approved by Purdue Animal Care and Use Committee (approval No. 1111000095) on January 1, 2021.

Neuroprotective mechanisms of red clover and soy isoflavones in Parkinson's disease models.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by nigrostriatal degeneration and the spreading of aggregated forms of the presynaptic protein α-synuclein (aSyn) throughout the brain. PD patients are currently only treated with symptomatic therapies, and strategies to slow or stop the progressive neurodegeneration underlying the disease's motor and cognitive symptoms are greatly needed. The time between the first neurobiochemical alterations and the initial presentation of symptoms is thought to span several years, and early neuroprotective dietary interventions could delay the disease onset or slow PD progression. In this study, we characterized the neuroprotective effects of isoflavones, a class of dietary polyphenols found in soy products and in the medicinal plant red clover (Trifolium pratense). We found that isoflavone-rich extracts and individual isoflavones rescued the loss of dopaminergic neurons and the shortening of neurites in primary mesencephalic cultures exposed to two PD-related insults, the environmental toxin rotenone and an adenovirus encoding the A53T aSyn mutant. The extracts and individual isoflavones also activated the Nrf2-mediated antioxidant response in astrocytes via a mechanism involving inhibition of the ubiquitin-proteasome system, and they alleviated deficits in mitochondrial respiration. Furthermore, an isoflavone-enriched soy extract reduced motor dysfunction exhibited by rats lesioned with the PD-related neurotoxin 6-OHDA. These findings suggest that plant-derived isoflavones could serve as dietary supplements to delay PD onset in at-risk individuals and mitigate neurodegeneration in the brains of patients.

Psychosocial impairment following mild blast-induced traumatic brain injury in rats.

Traumatic brain injury (TBI) is associated with increased risk for mental health disorders, impacting post-injury quality of life and societal reintegration. TBI is also associated with deficits in psychosocial processing, defined as the cognitive integration of social and emotional behaviors, however little is known about how these deficits manifest and their contributions to post-TBI mental health. In this pre-clinical investigation using rats, a single mild blast TBI (mbTBI) induced impairment of psychosocial processing in the absence of confounding physical polytrauma, post-injury motor deficits, affective abnormalities, or deficits in non-social behavior. Impairment severity correlated with acute upregulations of a known oxidative stress metabolite, 3-hydroxypropylmercapturic acid (3-HPMA), in urine. Resting state fMRI alterations in the acute post-injury period implicated key brain regions known to regulate psychosocial behavior, including orbitofrontal cortex (OFC), which is congruent with our previous report of elevated acrolein, a marker of neurotrauma and 3-HPMA precursor, in this region following mbTBI. OFC of mbTBI-exposed rats demonstrated elevated mRNA expression of metabotropic glutamate receptors 1 and 5 (mGluR1/5) and injection of mGluR1/5-selective agonist in OFC of uninjured rats approximated mbTBI-induced psychosocial processing impairment, demonstrating a novel role for OFC in this psychosocial behavior. Furthermore, OFC may serve as a hotspot for TBI-induced disruption of psychosocial processing and subsequent mental health disorders.

Mesenchymal Stem Cell-Derived Exosomes: Hope for Spinal Cord Injury Repair.

Spinal cord injury (SCI) is a devastating medical condition with profound social and economic impacts. Although research is ongoing, current treatment options are limited and do little to restore functionality. However, recent studies suggest that mesenchymal stem cell-derived exosomes (MSC-exosomes) may hold the key to exciting new treatment options for SCI patients. MSCs are self-renewing multipotent stem cells with multi-directional differentiation and can secrete a large number of exosomes (vesicles secreted into the extracellular environment through endocytosis, called MSC-exosomes). These MSC-exosomes play a critical role in repairing SCI through promoting angiogenesis and axonal growth, regulating inflammation and the immune response, inhibiting apoptosis, and maintaining the integrity of the blood-spinal cord barrier. Furthermore, they can be utilized to transport genetic material or drugs to target cells, and their relatively small size makes them able to permeate the blood-brain barrier. In this review, we summarize recent advances in MSC-exosome themed SCI treatments and cell-free therapies to better understand this newly emerging methodology.

Clioquinol improves motor and non-motor deficits in MPTP-induced monkey model of Parkinson's disease through AKT/mTOR pathway.

Despite decades of research into the pathology mechanisms of Parkinson's disease (PD), disease-modifying therapy of PD is scarce. Thus, searching for new drugs or more effective neurosurgical treatments has elicited much interest. Clioquinol (CQ) has been shown to have therapeutic benefits in rodent models of neurodegenerative disorders. However, it's neuroprotective role and mechanisms in PD primate models and PD patients, especially in the advanced stages, are not fully understood. Furthermore, issues such as spontaneous recovery of motor function and high symptom variability in different monkeys after the same toxic protocol, has not been resolved before the present study. In this study, we designed a chronic and long-term progressive protocol to generate a stabilized PD monkey model showed with classic motor and non-motor deficits, followed by treatment analysis of CQ. We found that CQ could remarkably improve the motor and non-motor deficits, which were based on the reduction of iron content and ROS level in the SN and further improvement in pathology. Meanwhile, we also showed that ferroptosis was probably involved in the pathogenesis of PD. In addition, the study shows a positive effect of CQ on AKT/mTOR survival pathway and a blocking effect on p53 medicated cell death in vivo and in vitro.

Iron overload resulting from the chronic oral administration of ferric citrate induces parkinsonism phenotypes in middle-aged mice.

Iron homeostasis is critical for maintaining normal brain physiological functions, and its mis-regulation can cause neurotoxicity and play a part in the development of many neurodegenerative disorders. The high incidence of iron deficiency makes iron supplementation a trend, and ferric citrate is a commonly used iron supplement. In this study, we found that the chronic oral administration of ferric citrate (2.5 mg/day and 10 mg/day) for 16 weeks selectively induced iron accumulation in the corpus striatum (CPu), substantia nigra (SN) and hippocampus, which typically caused parkinsonism phenotypes in middle-aged mice. Histopathological analysis showed that apoptosis- and oxidative stress-mediated neurodegeneration and dopaminergic neuronal loss occurred in the brain, and behavioral tests showed that defects in the locomotor and cognitive functions of these mice developed. Our research provides a new perspective for ferric citrate as a food additive or in clinical applications and suggests a new potential approach to develop animal models for Parkinson's disease (PD).

The Association of Iron and the Pathologies of Parkinson's Diseases in MPTP/MPP+-Induced Neuronal Degeneration in Non-human Primates and in Cell Culture.

Despite much efforts in the last few decades, the mechanism of degeneration of dopamine (DA) neurons in the substantia nigra (SN) in Parkinson's disease (PD) remains unclear. This represents a major knowledge gap in idiopathic and genetic forms of PD. Among various possible key factors postulated, iron metabolism has been widely suggested to be involved with fueling oxidative stress, a known factor in the pathogenesis of PD. However, the correlation between iron and DA neuron loss, specifically in the SN, has not been described in experimental animal models with great detail, with most studies utilizing rodents and, rarely, non-human primates. In the present study, aiming to gain further evidence of a pathological role of iron in PD, we have examined the correlation of iron with DA neuron loss in a non-human primate model of PD induced by MPTP. We report a significant iron accumulation accompanied by both DA degeneration in the SN and motor deficits in the monkey that displayed the most severe PD pathology and behavioral deficits. The other two monkeys subjected to MPTP displayed less severe PD pathologies and motor deficits, however, their SN iron levels were significantly lower than controls. These findings suggest that high iron may indicate and contribute to heightened MPP+-induced PD pathology in late or severe stages of PD, while depressed levels of iron may signal an early stage of disease. Similarly, using a cell culture preparation, we have found that high doses of ferric ammonium citrate (FAC), a factor known to enhance iron accumulation, increased MPP+-induced cell death in U251 and SH-SY5Y cells, and even in control cells. However, at low dose FAC restored or increased the viability of U251 and SH-SY5Y cells in the absence or presence of MPP+. These observations imply that high levels of iron likely contribute to or heighten MPP+ toxicity in the later stages of PD. While we report reduced iron levels in the earlier stages of MPTP induced PD, the significance of these changes remains to be determined.

Point-of-Care Tissue Analysis Using Miniature Mass Spectrometer.

The combination of direct sampling ionization and miniature mass spectrometer presents a promising technical pathway of point-of-care analysis in clinical applications. In this work, a miniature mass spectrometry system was used for analysis of tissue samples. Direct tissue sampling coupled with extraction spray ionization was used with a home-built miniature mass spectrometer, Mini 12. Lipid species in tissue samples were well profiled in rat brain, kidney, and liver in a couple of minutes. By incorporating a photochemical (Paternò-Büchi) reaction, fast identification of lipid C═C location was realized. Relative quantitation of the lipid C═C isomer was performed by calculating the intensity ratio C═C diagnostic product ions, by which FA 18:1 (Δ9)/FA 18:1 (Δ11) was found to change significantly in mouse cancerous breast tissue samples. Accumulation of 2-hydroxylglutarate in human glioma samples, not in normal brains, can also be easily identified for rapid diagnosis.

Peripheral Neuropathy and Hindlimb Paralysis in a Mouse Model of Adipocyte-Specific Knockout of Lkb1.

Brown adipose tissues (BAT) burn lipids to generate heat through uncoupled respiration, thus representing a powerful target to counteract lipid accumulation and obesity. The tumor suppressor liver kinase b1 (Lkb1) is a key regulator of cellular energy metabolism; and adipocyte-specific knockout of Lkb1 (Ad-Lkb1 KO) leads to the expansion of BAT, improvements in systemic metabolism and resistance to obesity in young mice. Here we report the unexpected finding that the Ad-Lkb1 KO mice develop hindlimb paralysis at mid-age. Gene expression analyses indicate that Lkb1 KO upregulates the expression of inflammatory cytokines in interscapular BAT and epineurial brown adipocytes surrounding the sciatic nerve. This is followed by peripheral neuropathy characterized by infiltration of macrophages into the sciatic nerve, axon degeneration, reduced nerve conductance, and hindlimb paralysis. Mechanistically, Lkb1 KO reduces AMPK phosphorylation and amplifies mammalian target-of-rapamycin (mTOR)-dependent inflammatory signaling specifically in BAT but not WAT. Importantly, pharmacological or genetic inhibition of mTOR ameliorates inflammation and prevents paralysis. These results demonstrate that BAT inflammation is linked to peripheral neuropathy.

Exogenous Acrolein intensifies sensory hypersensitivity after spinal cord injury in rat.

Acrolein, an α,ß-unsaturated aldehyde associated with oxidative stress, is also a major toxic component of tobacco cigarette smoke, which has been reported in the clinic to coincide with the exacerbation of neuropathic pain after SCI. Previous reports have shown that acrolein involvement in spinal cord injury (SCI) is crucial to the development and persistence of neuropathic pain. Through the activation and upregulation of the transient receptor protein ankyrin-1 (TRPA1) cation channel, acrolein is capable of sensitizing the central nervous system in the acute and chronic stages of SCI. Here, we report that the acute or delayed nasal exposure of acrolein, apart from cigarette smoke but at concentrations similar to that found in cigarette smoke, resulted in increased neuropathic pain behaviors in a rat model of contusion SCI. We also found that this hyperalgesia occurred concurrently with an augmentation in systemic acrolein, detected by an acrolein-glutathione metabolite in the urine. The application of an acrolein scavenger, phenelzine, was shown to reduce the hyperalgesic effect of acrolein inhalation. The previously determined ability of acrolein to bind to and activate the TRPA1 channel and elicit algesic responses may be a mechanism of the phenomenon seen in this study. Upon the exposure to actual cigarette smoke after SCI, intensified neuropathic pain behaviors were also observed and persisted for at least 1week after the cessation of the exposure period. Taken together, these results indicate that cigarette smoke, through mechanisms involving acrolein, poses a threat to the vulnerable CNS after SCI and can contribute to neuropathic pain. This investigation also provides further evidence for the potential utility of acrolein scavengers as a therapeutic strategy in SCI-resultant neuropathic pain.

Dimercaprol is an acrolein scavenger that mitigates acrolein-mediated PC-12 cells toxicity and reduces acrolein in rat following spinal cord injury.

Acrolein is one of the most toxic byproducts of lipid peroxidation, and it has been shown to be associated with multiple pathological processes in trauma and diseases, including spinal cord injury, multiple sclerosis, and Alzheimer's disease. Therefore, suppressing acrolein using acrolein scavengers has been suggested as a novel strategy of neuroprotection. In an effort to identify effective acrolein scavengers, we have confirmed that dimercaprol, which possesses thiol functional groups, could bind and trap acrolein. We demonstrated the reaction between acrolein and dimercaprol in an abiotic condition by nuclear magnetic resonance spectroscopy. Specifically, dimercaprol is able to bind to both the carbon double bond and aldehyde group of acrolein. Its acrolein scavenging capability was further demonstrated by in vitro results that showed that dimercaprol could significantly protect PC-12 cells from acrolein-mediated cell death in a dose-dependent manner. Furthermore, dimercaprol, when applied systemically through intraperitoneal injection, could significantly reduce acrolein contents in spinal cord tissue following a spinal cord contusion injury in rats, a condition known to have elevated acrolein concentration. Taken together, dimercaprol may be an effective acrolein scavenger and a viable candidate for acrolein detoxification.

Nondermal irritating hyperosmotic nanoemulsions reduce treatment times in a contamination model of wound healing.

Increased microbial burden within the wound often complicates wound healing and may lead to subsequent infection or delayed healing. Here, we investigate a novel topical for addressing wound contamination that utilizes hyperosmotic saccharides with a cell membrane disrupting emulsion. These hyperosmotic nanoemulsions (HNE) were administered topically in a full-thickness biopsy model of wound healing. Results show that HNE were well tolerated in noninfected animals with no indications of dermal irritation or acute toxicity. Additionally, HNE was able to reduce bacterial bioburden (Escherichia coli and Enterococcus faecalis) levels by 3 logs within 24 h when wounds were inoculated with 5 × 10(6) total CFU. These bactericidal values were similar to wounds treated with silver sulfadiazine. Wound closure showed HNE wounds closed in 7.6 ± 0.2 days while SSD and control required 10.2 ± 0.4 and 10.4 ± 0.3 days, respectively. HNE maintained a moist wound environment, were well debrided, and exhibited improved hemostatic response. Further histological examination revealed enhanced granulation tissue as compared to silver sulfadiazine and control cohorts. These results were corroborated with 3D topographical imprints of the wounds at day 14 which qualitatively showed a smoother surface. In contrast, silver sulfadiazine appeared to delay wound closure. Finally, dermal sensitization and irritation studies conducted in guinea pig and rabbits did not reveal any acute dermal side effects from HNE exposure. The cumulative data indicates nonantibiotic-based HNEs may be a promising topical treatment for the management of contaminated wounds.

Identification and quantitation of lipid C=C location isomers: A shotgun lipidomics approach enabled by photochemical reaction.

The field of lipidomics has been significantly advanced by mass spectrometric analysis. The distinction and quantitation of the unsaturated lipid isomers, however, remain a long-standing challenge. In this study, we have developed an analytical tool for both identification and quantitation of lipid C=C location isomers from complex mixtures using online Paternò-Büchi reaction coupled with tandem mass spectrometry (MS/MS). The potential of this method has been demonstrated with an implementation into shotgun lipid analysis of animal tissues. Among 96 of the unsaturated fatty acids and glycerophospholipids identified from rat brain tissue, 50% of them were found as mixtures of C=C location isomers; for the first time, to our knowledge, the quantitative information of lipid C=C isomers from a broad range of classes was obtained. This method also enabled facile cross-tissue examinations, which revealed significant changes in C=C location isomer compositions of a series of fatty acids and glycerophospholipid (GP) species between the normal and cancerous tissues.

Acrolein contributes to TRPA1 up-regulation in peripheral and central sensory hypersensitivity following spinal cord injury.

Acrolein, an endogenous aldehyde, has been shown to be involved in sensory hypersensitivity after rat spinal cord injury (SCI), for which the pathogenesis is unclear. Acrolein can directly activate a pro-algesic transient receptor protein ankyrin 1 (TRPA1) channel that exists in sensory neurons. Both acrolein and TRPA1 mRNA are elevated post SCI, which contributes to the activation of TRPA1 by acrolein and consequently, neuropathic pain. In the current study, we further showed that, post-SCI elevation of TRPA1 mRNA exists not only in dorsal root ganglias but also in both peripheral (paw skin) and central endings of primary afferent nerves (dorsal horn of spinal cord). This is the first indication that pain signaling can be over-amplified in the peripheral skin by elevated expressions of TRPA1 following SCI, in addition over-amplification previously seen in the spinal cord and dorsal root ganglia. Furthermore, we show that acrolein alone, in the absence of physical trauma, could lead to the elevation of TRPA1 mRNA at various locations when injected to the spinal cord. In addition, post-SCI elevation of TRPA1 mRNA could be mitigated using acrolein scavengers. Both of these attributes support the critical role of acrolein in elevating TRPA1 expression through gene regulation. Taken together, these data indicate that acrolein is likely a critical causal factor in heightening pain sensation post-SCI, through both the direct binding of TRPA1 receptor, and also by boosting the expression of TRPA1. Finally, our data also further support the notion that acrolein scavenging may be an effective therapeutic approach to alleviate neuropathic pain after SCI. We propose that the trauma-mediated elevation of acrolein causes neuropathic pain through at least two mechanisms: acrolein stimulates the production of transient receptor protein ankyrin 1 (TRPA1) in both central and peripheral locations, and it activates TRPA1 channels directly. Therefore, acrolein appears to be a critical factor in the pathogenesis of post-SCI sensory hypersensitivity, becoming a novel therapeutic target to relieve both acute and chronic post-SCI neuropathic pain.

Acute systemic accumulation of acrolein in mice by inhalation at a concentration similar to that in cigarette smoke.

Cigarette smoke is an important environmental factor associated with a wide array of public health concerns. Acrolein, a component of tobacco smoke and a known toxin to various cell types, may be a key pathological factor mediating the adverse effects linked with tobacco smoke. Although acrolein is known to accumulate in the respiratory system after acute nasal exposure, it is not clear if it accumulates systemically, and less is known in the nervous system. The aim of this study was to assess the degree of acrolein accumulation in the circulation and in the spinal cord following acute acrolein inhalation in mice. Using a laboratory-fabricated inhalation chamber, we found elevated urinary 3-HPMA, an acrolein metabolite, and increased acrolein adducts in the spinal cord after weeks of nasal exposure to acrolein at a concentration similar to that in tobacco smoke. The data indicated that acrolein is absorbed into the circulatory system and some enters the nervous system. It is expected that these findings may facilitate further studies to probe the pathological role of acrolein in the nervous system resulting from smoke and other external sources.