Dexmedetomidine attenuates ferroptosis by Keap1-Nrf2/HO-1 pathway in LPS-induced acute kidney injury.

Previous research has demonstrated that Dexmedetomidine (DEX), an α2 adrenergic agonist commonly used for its sedative and analgesic properties, can attenuate lipopolysaccharide (LPS)-induced acute kidney injury (AKI). This study explores the possibility that DEX's protective effects in LPS-induced AKI are mediated through the inhibition of ferroptosis, a form of regulated cell death characterized by iron-dependent lipid peroxidation, and the activation of the antioxidant response through the Keap1/Nrf2/HO-1 signaling pathway. We induced AKI in 42 mice using LPS and divided them into six groups: saline control, LPS, LPS + DEX, LPS + Ferrostatin-1 (LPS + Fer-1; a ferroptosis inhibitor), LPS + DEX with α2-receptor antagonist Altipamizole (LPS + DEX + ATI), and LPS + DEX with Nrf2 inhibitor ML385 (LPS + DEX + ML385). After 24 h, we analyzed blood and kidney tissues. LPS exposure resulted in AKI, with increased serum creatinine, BUN, and cystatin C, and tubular damage, which DEX and Fer-1 ameliorated. However, Altipamizole and ML385 negated these improvements. The LPS group exhibited elevated oxidative stress markers and mitochondrial damage, reduced by DEX and Fer-1, but not when α2-adrenergic or Nrf2 pathways were blocked. Nrf2 and HO-1 expression declined in the LPS group, rebounded with LPS + DEX and LPS + Fer-1, and fell again with inhibitors; inversely, Keap1 expression varied. Our results demonstrate that DEX may protect against LPS-induced AKI, at least partially by regulating ferroptosis and the α2-adrenergic receptor/Keap1/Nrf2/HO-1 pathway, suggesting a potential therapeutic role for DEX in AKI management by modulating cell death and antioxidant defenses.

Resolution-increased fiber-optic strain sensor with a large dynamic range driven by white light.

The white light interferometer is advantageous for wavelength division multiplexing (WDM), but the excessive noise floor limits its application in practicality. In this Letter, we propose a fiber-optic sensor driven by a broadband light source, which uses a fiber-optic Fabry-Perot cavity and a reference interferometer to enhance strain resolution. In the experiment, the strain resolution of a 5.86 m resonant sensor is 18.5 fɛ/H z at 1.5 kHz, while the maximum detectable signal is over 230 rad at 1 kHz. With low cost, this method provides a new, to the best of our knowledge, solution for WDM sensing arrays with a large dynamic range.

The objectively measured walking speed and risk of hypertension in Chinese older adults: a prospective cohort study.

This study aims to investigate the longitudinal association between objectively measured walking speed and hypertension and to explore the potential effect modification of obesity on this association in Chinese older adults. The data from the Chinese Health and Retirement Prospective Cohort Study (CHARLS) during 2011-2015 was used. Walking speed was assessed by measuring the participants' usual gait in a 2.5 m course, and it was divided into four groups according to the quartiles (Q1, Q2, Q3, and Q4). A total of 2733 participants ≥60 years old were eligible for the analyses. After a follow-up of 4 years, 26.9% occurred hypertension. An inverse association was observed between walking speed and the risk of hypertension. There was an interaction between body mass index (BMI) and walking speed for the hypertension risk (P = 0.010). the association of walking speed with hypertension was stronger in overweight and obese participants (Q2, OR: 0.54, 95%CI = 0.34-0.85, P = 0.009; Q3, OR: 0.69, 95%CI = 0.44-1.08, P = 0.106; Q4, OR: 0.62, 95%CI = 0.39-0.98, P = 0.039). However, this association was not significant among lean ones. A similar trend was observed for systolic and diastolic blood pressure. In conclusion, higher walking speed was longitudinally associated with a lower risk of hypertension in Chinese older adults, especially among overweight and obese participants.

The effects of thioredoxin peroxidase from Cysticercus cellulosae excretory-secretory antigens on TGF-ß signaling pathway and Th17 cells differentiation in Jurkat cells by transcriptomics.

Thioredoxin peroxidase (TPx) protein from the excretory-secretory antigens (ESAs) of Cysticercus cellulosae (C. cellulosae) has been shown to regulate the differentiation of host Treg and Th17 cells, resulting in an immunosuppressive response dominated by Treg cells. However, the molecular mechanism by which TPx protein from the ESAs of C. cellulosae regulates the imbalance of host Treg/Th17 cell differentiation has not been reported. TPx protein from porcine C. cellulosae ESAs was used to stimulate Jurkat cells activated with PMA and ionomycin at 0, 24, 48, and 72 h. Transcriptomic analysis was performed to investigate the signaling pathways associated with Jurkat cells differentiation regulated by TPx protein from C. cellulosae ESAs. Gene Set Enrichment Analysis (GSEA) revealed that TPx protein from porcine C. cellulosae ESAs could induce upregulation of the TGF-ß signaling pathway and downregulation of Th17 cell differentiation in Jurkat cells. TPx protein from porcine C. cellulosae ESAs can activate the TGF-ß signaling pathway in Jurkat cells, thereby regulating the differentiation of Treg/Th17 cells and leading to an immunosuppressive response dominated by Treg cells, enabling evasion of the host immune attack. This study provides a foundation for further validation of these pathways and further elucidates the molecular mechanisms underlying immune evasion caused by porcine C. cellulosae.

Living alone and the risk of depressive symptoms: a cross-sectional and cohort analysis based on the China Health and Retirement Longitudinal Study.

BACKGROUND: There were a few studies that examined the longitudinal association between living alone and depressive symptoms, and the vast majority of them were conducted in patients with certain diseases, such as heart failure, cancer, and glaucoma. This study aimed to examine the association between living alone and depressive symptoms in a large representative older Chinese population. METHODS: The China Health and Retirement Longitudinal Study (CHARLS) data from 2015 to 2018 were used. Living alone was defined as participants who did not live with others ever or more than 11 months in the past year at baseline. Depressive symptoms were measured using the 10-item Center for Epidemiological Studies-Depression Scale (CES-D10). The multivariate logistic regression was used to estimate the relationship between living alone and depressive symptoms. RESULTS: There were 5,311 and 2,696 participants ≥ 60 years old included in the cross-sectional and cohort analysis, respectively. The risk of depressive symptoms in participants who lived alone was significantly higher than those who lived with others in both cross-sectional (OR:1.33; 95%CI:1.14,1.54) and cohort analysis (OR:1.23; 95%CI:0.97,1.55). There was a significant interaction between financial support and living alone (Pinteraction = 0.008) on the risk of depressive symptoms. Stratified analyses showed that, compared to those who lived with others, the risk of depressive symptoms in participants who lived alone increased by 83% (OR:1.83; 95%CI:1.26,2.65) in participants receiving lower financial support. However, we did not find statistically significant associations in participants with medium (OR:1.10; 95%CI: 0.74,1.63) and higher financial support (OR: 0.87; 95%CI: 0.53,1.41). CONCLUSION: Living alone was associated with a higher risk of depressive symptoms in the Chinese older population, and this association was moderated by the receipt of financial support. Living alone may be an effective and easy predictor for early identification of high-risk populations of depression in the older population.

Associations of pyrethroid exposure with skeletal muscle strength and mass.

This study aimed to examine the associations of pyrethroid exposure with handgrip strength and skeletal muscle mass and potential modification effects in US adults. The data from the National Health and Nutrition Examination Survey was used. Handgrip strength was determined with a handgrip dynamometer, and we quantified muscle mass by using the appendicular skeletal muscle index (ASMI). Urinary 3-Phenoxybenzoic Acid (3-PBA), a validated biomarker for pyrethroid exposure, was used in the primary analysis. After adjusting for other covariates, participants exposed to the highest tertile of 3-PBA exposure had significantly lower handgrip strength (ß = -1.88, 95% CI: -3.29, -0.23, P = 0.026) than those exposed to the lowest tertile of 3-PBA. Similarly, the 3-PBA exposure was marginally significantly associated with ASMI (Tertile 3 vs. Tertile 1: ß = -0.07, 95% CI: -0.14, -0.01, P = 0.056). Significant interactions were found between 3-PBA and body mass index (BMI) on handgrip strength and ASMI (P interaction < 0.05), which indicated a potential moderation effect of BMI on the associations. In conclusion, pyrethroid exposure was adversely associated with handgrip strength and skeletal muscle mass, especially in overweight and obese populations. Further studies are warranted to confirm our results and to explore the potential mechanisms.

Effects of dexmedetomidine administration on outcomes in critically ill patients with acute kidney injury: A propensity score-matching analysis.

PURPOSE: To evaluate the effects of dexmedetomidine (DEX) on outcomes of critically ill patients with acute kidney injury (AKI). MATERIALS AND METHODS: Data were extracted from the Medical Information Mart for Intensive Care III database (MIMIC III). Propensity score matching (PSM) analysis (1 : 3), Cox proportional hazards model, linear regression and logistic regression model were used to assess the effect of DEX on clinical outcomes. RESULTS: After PSM, 324 pairs of patients were matched between the patients with DEX administration and those without. DEX administration was associated with decreased in-hospital mortality (hazard ratio (HR) 0.287; 95% CI 0.151 - 0.542; p < 0.001) and 90-day mortality (HR 0.344; 95% CI 0.221 - 0.534; p < 0.001), and it was also associated with reduced length of stay (LOS) in ICU (4.54 (3.13,7.72) vs. 5.24 (3.15,10.91), p < 0.001) and LOS in hospital (11.63 (8.02,16.79) vs 12.09 (7.83,20.44), p = 0.002). Subgroup analysis showed that the above associations existed only in the mild and moderate AKI subgroups, but not in the severe AKI subgroup. Nevertheless, DEX administration was not associated with recovery of renal function (HR 1.199; 95% CI 0.851 - 1.688; p = 0.300). CONCLUSION: DEX administration improved outcomes in critically ill patients with mild and moderate AKI and could be a good choice of sedation.

Effects of Cysticercus cellulosae Excretory-Secretory Antigens on the TGF-ß Signaling Pathway and Th17 Cell Differentiation in Piglets, a Proteomic Analysis.

Excretory-secretory antigens (ESAs) of Cysticercus cellulosae can directly regulate the proliferation and differentiation of host T regulatory (Treg) cells, thus inhibiting host immune responses. However, previous studies have only focused on this phenomenon, and the molecular mechanisms behind the ways in which C. cellulosae ESAs regulate the differentiation of host Treg/Th17 cells have not been reported. We collected CD3+ T cells stimulated by C. cellulosae ESAs through magnetic bead sorting and used label-free quantification (LFQ) proteomics techniques to analyze the signaling pathways of C. cellulosae ESAs regulating Treg/Th17 cell differentiation. Through gene set enrichment analysis (GSEA), we found that C. cellulosae ESAs could upregulate the TGF-ß signaling pathway and downregulate Th17 cell differentiation in piglet T cells. Interestingly, we also found that the IL-2/STAT5 signaling pathway also affects the downregulation of Th17 cell differentiation. C. cellulosae ESAs activate the TGF-ß signaling pathway and the IL-2/STAT5 signaling pathway in host T cells to further regulate the differentiation of Treg/Th17 cells in order to evade host immune attack. This study lays the foundation for the subsequent verification of these pathways, and further clarifies the molecular mechanism of C. cellulosae-mediated immune evasion.

Dexmedetomidine Alleviates Ischemia/Reperfusion-Associated Acute Kidney Injury by Enhancing Autophagic Activity via the α2-AR/AMPK/mTOR Pathway.

BACKGROUND: Dexmedetomidine (DEX) reportedly protects against ischemia-reperfusion (I/R) injury and associated damage to the kidneys, but the underlying mechanisms have yet to be established. METHODS: Unilateral nephrectomy was performed in Wistar rats, and the remaining kidney was clamped for 1 h prior to reperfusion to establish an experimental model system. These animals were then randomized into Sham, DEX + Sham, DEX + I/R, ATI (Altepamizole, α2-adrenergic receptor inhibitor) + DEX + I/R, and 3-MA (3-methyladenine, autophagy inhibitor) + DEX + I/R groups. Serum renal function biomarkers, acute kidney injury (AKI) histopathological scores, serum inflammatory factors, redox biomarkers, markers of autophagic flux, and autophagosome numbers were assessed. Levels of proteins related to the autophagic pathway, including mTOR and AMPK, were also analyzed. RESULTS: Serum creatinine and urea nitrogen levels in the I/R group were significantly elevated over those in sham control rats, as were AKI scores, serum inflammatory cytokine concentrations (IL-6, IL-1ß, and TNF-α), and serum levels of the oxidative stress biomarker malondialdehyde (MDA). All of these parameters were significantly reduced in the DEX + I/R group relative to I/R model rats. I/R group rats also exhibited significant decreases in renal levels of autophagic flux-related biomarkers and autophagosome numbers relative to sham controls, while DEX administration partially restored normal autophagic flux in these rats. Acute I/R also suppress the expression of AMPK in the kidney while increasing mTOR expression, and DEX reversed these effects. The beneficial impact of DEX on I/R-associated AKI was ablated by ATI or 3-MA administration. CONCLUSIONS: These analyses provide strong evidence for the ability of DEX to protect against I/R-associated AKI via the α2-AR/AMPK/mTOR pathway-mediated enhancement of autophagic activity.

Regulation of piglet T-cell immune responses by thioredoxin peroxidase from Cysticercus cellulosae excretory-secretory antigens.

Taenia solium (T. solium) cysticercosis is a serious threat to human health and animal husbandry. During parasitization, Cysticercus cellulosae (C. cellulosae) can excrete and secrete antigens that modulate the host's T-cell immune responses. However, the composition of C. cellulosae excretory-secretory antigens (ESAs) is complex. This study sought to identify the key molecules in C. cellulosae ESAs involved in regulating T-cell immune responses. Thus, we screened for thioredoxin peroxidase (TPx), with the highest differential expression, as the key target by label-free quantification proteomics of C. cellulosae and its ESAs. In addition, we verified whether TPx protein mainly exists in C. cellulosae ESAs. The TPx recombinant protein was prepared by eukaryotic expression, and ESAs were used as the experimental group to further investigate the effect of TPx protein on the immune response of piglet T cells in vitro. TPx protein induced an increase in CD4+ T cells in piglet peripheral blood mononuclear cells (PBMCs), while CD8+ T cells did not change significantly. This resulted in an imbalance in the CD4+/CD8+ T-cell ratio and an increase in CD4+CD25+Foxp3+ Treg cells in the PBMCs. In addition, TPx protein initiated T helper 2 (Th2)-type immune responses by secreting IL-4 and IL-10 and suppressed Th1/Th17-type immune responses. The results showed that ESAs were involved in regulating piglet T-cell immune responses cells. This suggests that TPx protein found in ESAs plays an essential role to help the parasite evade host immune attack. Moreover, this lays a foundation for the subsequent exploration of the mechanism through which TPx protein regulates signaling molecules to influence T-cell differentiation.

Analysis of immune response in BALB/c mice immunized with recombinant plasmids pMZ-X3-Ts14-3-3.3 and pMZ-X3-sp-Ts14-3-3.3 of Taenia solium.

There is a lack of vaccine against human cysticercosis, thus making a huge population at the risk of infection. In this study, we chose a novel potential antigen molecule Taenia solium 14-3-3.3 (Ts14-3-3.3) and optimized it as sp-Ts14-3-3.3 (sp is immunoglobulin H chain V-region precursor, partial) in order to construct recombinant plasmids pMZ-X3-Ts14-3-3.3 and pMZ-X3-sp-Ts14-3-3.3. BALB/c mice were divided into four groups for immunization: pMZ-X3-Ts14-3-3.3, pMZ-X3-sp-Ts14-3-3.3, pMZ-X3 plasmid control group and PBS control group. Compared with two control groups, the proliferation level of splenic lymphocytes increased significantly in pMZ-X3-Ts14-3-3.3 and pMZ-X3-sp-Ts14-3-3.3 groups and reached the maximum in week 6. And the same case arose as cytokines associated with Th1 response, IFN-γ, and IL-2 while those with Th2 response, IL-4, IL-10 went up and reached the maximum in week 4. The levels of serum specific IgG, IgG1 and IgG2a rose and reached the maximum in week 6, 4 and 6, respectively. Meanwhile, the proportion of CD4+/CD8+ splenic T lymphocytes increased and reached the peak in week 6. The results indicated that the recombinant plasmids pMZ-X3-Ts14-3-3.3 and pMZ-X3-sp-Ts14-3-3.3 can induce specific cellular and humoral immune responses in BALB/c mice with immunization. Notably, the recombinant plasmid pMZ-X3-sp-Ts14-3-3.3 has a better immune effect, which proves that Ts14-3-3.3 enjoys a higher possibility as a potential antigen molecule to T. solium vaccine.

Proteomic analysis of Taenia solium cysticercus and adult stages.

Taenia solium (T. solium) cysticercosis is a neglected parasitic zoonosis that occurs in developing countries. Since T. solium has a complex life cycle that includes eggs, oncospheres, cysticerci, and adults, presumably many proteins are produced that enable them to survive and establish an infection within the host. The objectives of this study were to perform a comparative proteomic analysis of two ontogenetic stages of T. solium (cysticerci and adult) and to analyze their differential expression of proteins. Methods proteins were separated by High Performance Liquid Chromatography (HPLC) fractionation, and protein samples were also digested in liquid and identified by liquid chromatography tandem mass spectrometry (LC-MS/MS); the differentially expressed proteins were then processed by a bioinformatics analysis and verified by parallel reaction monitoring (PRM). Results we identified 2,481 proteins by label-free quantitative proteomics. Then differentially expressed proteins were screened under P values < 0.05 and 2 fold change, we found that 293 proteins up-regulated and 265 proteins down-regulated. Discussion through the bioinformatics analysis, we analyzed the differences types and functions of proteins in the Taenia solium and cysticercus, the data will provide reference value for studying the pathogenic mechanism of the two stages and the interaction with the host, and also support for further experimental verification.

Cysticercus cellulosae Regulates T-Cell Responses and Interacts With the Host Immune System by Excreting and Secreting Antigens.

Cysticercus cellulosae (C. cellulosae) excretes and secretes antigens during the parasitic process to regulate the host immune response; however, resulting immune response and cytokine production in the host during infection still remains unclear. We used C. cellulosae crude antigens (CAs) as controls to explore the effect of excretory secretory antigens (ESAs) on T-cell immune responses in piglets. C. cellulosae ESAs induced imbalanced CD4+/CD8+ T-cell proportions, increased the CD4+Foxp3+ and CD8+Foxp3+ T-cell frequencies, and induced lymphocytes to produce interleukin-10, which was mainly attributed to CD4+ and CD4-CD8- T cells. The ESAs also induced Th2-type immune responses. The results showed that the ability of C. cellulosae to escape the host immune attacks and establish a persistent infection may be related to host immune response regulation by the ESAs.

An Improved CNN Architecture to Diagnose Skin Cancer in Dermoscopic Images Based on Wildebeest Herd Optimization Algorithm.

Skin cancer is one of the most common types of cancers that is sometimes difficult for doctors and experts to diagnose. The noninvasive dermatoscopic method is a popular method for observing and diagnosing skin cancer. Because this method is based on ocular inference, the skin cancer diagnosis by the dermatologists is difficult, especially in the early stages of the disease. Artificial intelligence is a proper complementary tool that can be used alongside the experts to increase the accuracy of the diagnosis. In the present study, a new computer-aided method has been introduced for the diagnosis of the skin cancer. The method is designed based on combination of deep learning and a newly introduced metaheuristic algorithm, namely, Wildebeest Herd Optimization (WHO) Algorithm. The method uses an Inception convolutional neural network for the initial features' extraction. Afterward, the WHO algorithm has been employed for selecting the useful features to decrease the analysis time complexity. The method is then performed to an ISIC-2008 skin cancer dataset. Final results of the feature selection based on the proposed WHO are compared with three other algorithms, and the results have indicated good results for the system. Finally, the total diagnosis system has been compared with five other methods to indicate its effectiveness against the studied methods. Final results showed that the proposed method has the best results than the comparative methods.

Potassium Acetate-Catalyzed Double Decarboxylative Transannulation To Access Highly Functionalized Pyrroles.

The development of new synthetic strategies for the efficient construction of versatile pyrrole pharmacores, especially in an operationally simple and environmentally benign fashion, still remains a momentous yet challenging goal. Here, we report a KOAc-catalyzed double decarboxylative transannulation between readily accessible oxazolones and isoxazolidinediones. This transformation represents a new way for skeletal remodeling by utilizing CO2 moiety as traceless activating and directing groups in both reaction partners. The synthetic value is evidenced by the rapid preparation of a broad spectrum of highly functionalized 3-carbamoyl-4-aryl pyrroles in good to excellent yields with exclusive regio-control, including the important Atorvastatin core.

Internalization of HMGB1 (High Mobility Group Box 1) Promotes Angiogenesis in Endothelial Cells.

OBJECTIVE: In patients with peripheral artery disease, blockages in arterioles <1 mm cannot be treated surgically, and there are currently few effective medicines. Studies have shown that inflammation in ischemic tissue is related to injury recovery and angiogenesis, but insufficient attention has been paid to this area. Studies have suggested that HMGB1 (high mobility group protein 1), which is released by ischemic tissue, promotes angiogenesis, but the mechanism is not entirely clear. In this study, we tested the internalization of HMGB1 in endothelial cells and investigated a novel proangiogenic pathway. Approach and Results: Using green fluorescent protein-tagged HMGB1 to stimulate endothelial cells, we demonstrated HMGB1 internalization via dynamin and RAGE (receptor for advanced glycation end products)-dependent signaling. Using a fluorescence assay, we detected internalized protein fusion to lysosomes, followed by activation of CatB (cathepsin B) and CatL (cathepsin L). The latter promoted the release of VEGF (vascular endothelial growth factor)-A and endoglin and upregulated the capacities of cell migration, proliferation, and tube formation in endothelial cells. We identified that the cytokine-induced fragment-a key functional domain in HMGB1-mediates the internalization and angiogenic function of HMGB1. We further confirmed that HMGB1 internalization also occurs in vivo in endothelial cells and promotes angiogenesis in mouse femoral artery ligation. CONCLUSIONS: In this study, we identified a novel pathway of HMGB1 internalization-induced angiogenesis in endothelial cells. This finding sheds light on the regulatory role of inflammatory factors in angiogenesis through cell internalization and opens a new door to understand the relationship between inflammation and angiogenesis in ischemic diseases.

Nickel-catalyzed intermolecular oxidative Heck arylation driven by transfer hydrogenation.

The conventional oxidative Heck reaction between aryl boronic acids and alkenes typically involved the PdII/Pd0/PdII catalytic cycle incorporating an external oxidant and often suffered C=C bond isomerization for internal alkyl-substituted alkenes via chain-walking. Herein, we demonstrate that the regioselectivity (γ-selectivity vs. δ-selectivity) and pathway selectivity (hydroarylation vs. oxidative Heck coupling) of a directed Ni-catalyzed alkene arylation can be controlled by judicious tuning of the coordination environment around the nickel catalyst via optimization of an appropriate phosphine ligand and directing group. In this way, the Ni(0)-catalyzed oxidative Heck arylation that relies on transfer hydrogenation of an acceptor olefin is developed with excellent E/Z selectivity and regioselectivity. Mechanistic investigations suggest that the addition of the acceptor is crucial for lowering the energy for carbometalation and for enabling catalytic turnover.

Bi(III)-Catalyzed Enantioselective Allylation Reactions of Ketimines.

Chiral homoallylic amines not only are found in pharmaceutically relevant compounds but also serve as versatile building blocks for chemical synthesis. However, catalytic allylation of ketimines with allylboronates, an attractive approach to synthesize chiral homoallylic amine scaffolds remain scarce. Herein, we develop a highly enantioselective allylation of isatin-derived ketimines with boron allylation reagents catalyzed by a Bi(OAc)3-chiral phosphoric acid catalyst system. The reactions are remarkably efficient and mild, most of which were completed in less than an hour at room temperature with only 1/2 mol% (Bi(OAc)3/CPA) catalyst loading. A wide range of chiral 3-allyl 3-aminooxindoles were obtained in excellent yields and enantioselectivities. The synthetic utility was demonstrated by efficient formal synthesis of (+)-AG-041R and (-)-psychotriasine. Preliminary mechanism was studied by control experiments and theoretical calculations.

Mechanism and Origins of Chemo- and Stereoselectivities of Aryl Iodide-Catalyzed Asymmetric Difluorinations of ß-Substituted Styrenes.

The mechanism of the aryl iodide-catalyzed asymmetric migratory geminal difluorination of ß-substituted styrenes ( Banik et al. Science 2016, 353, 51 ) has been explored with density functional theory computations. The computed mechanism consists of (a) activation of iodoarene difluoride (ArIF2), (b) enantiodetermining 1,2-fluoroiodination, (c) bridging phenonium ion formation via SN2 reductive displacement, and (d) regioselective fluoride addition. According to the computational model, the ArIF2 intermediate is stabilized through halogen-π interactions between the electron-deficient iodine(III) center and the benzylic substituents at the catalyst stereogenic centers. Interactions with the catalyst ester carbonyl groups (I(III)+···O) are not observed in the unactivated complex, but do occur upon activation of ArIF2 through hydrogen-bonding interactions with external Brønsted acid (HF). The 1,2-fluoroiodination occurs via alkene complexation to the electrophilic, cationic I(III) center followed by C-F bond formation anti to the forming C-I bond. The bound olefin and the C-I bond of catalyst adopt a spiro arrangement in the favored transition structures but a nearly periplanar arrangement in the disfavored transition structures. Multiple attractive non-covalent interactions, including slipped π···π stacking, C-H···O, and C-H···π interactions, are found to underlie the high asymmetric induction. The chemoselectivity for 1,1-difluorination versus 1,2-difluorination is controlled mainly by (1) the steric effect of the substituent on the olefinic double bond and (2) the nucleophilicity of the carbonyl oxygen of substrate.