Mechanistic Overview

Metabolic Reprogramming via Microglial Glycolysis Inhibition starts from the claim that modulating HK2 within the disease context of neurodegeneration can redirect a disease-relevant process. The original description reads: "## Molecular Mechanism and Rationale The therapeutic strategy of metabolic reprogramming through microglial glycolysis inhibition represents a novel approach to neurodegeneration that exploits the fundamental metabolic differences between inflammatory M1 and anti-inflammatory M2 microglial phenotypes. At the molecular level, this intervention targets hexokinase 2 (HK2), the rate-limiting enzyme in glycolysis that catalyzes the phosphorylation of glucose to glucose-6-phosphate. HK2 is particularly critical in microglia due to its mitochondrial localization and role in coupling glucose metabolism to cellular energy demands. In neurodegeneration, activated microglia predominantly adopt an M1 pro-inflammatory phenotype characterized by enhanced glycolytic flux and reduced oxidative phosphorylation (OXPHOS).

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Mechanistic Overview

Metabolic Reprogramming via Microglial Glycolysis Inhibition starts from the claim that modulating HK2 within the disease context of neurodegeneration can redirect a disease-relevant process. The original description reads: "## Molecular Mechanism and Rationale The therapeutic strategy of metabolic reprogramming through microglial glycolysis inhibition represents a novel approach to neurodegeneration that exploits the fundamental metabolic differences between inflammatory M1 and anti-inflammatory M2 microglial phenotypes. At the molecular level, this intervention targets hexokinase 2 (HK2), the rate-limiting enzyme in glycolysis that catalyzes the phosphorylation of glucose to glucose-6-phosphate. HK2 is particularly critical in microglia due to its mitochondrial localization and role in coupling glucose metabolism to cellular energy demands. In neurodegeneration, activated microglia predominantly adopt an M1 pro-inflammatory phenotype characterized by enhanced glycolytic flux and reduced oxidative phosphorylation (OXPHOS). This metabolic signature is orchestrated by the transcription factor hypoxia-inducible factor 1α (HIF-1α), which upregulates glycolytic enzymes including HK2, phosphofructokinase (PFK), and lactate dehydrogenase A (LDHA). Simultaneously, HIF-1α suppresses mitochondrial biogenesis and OXPHOS machinery through inhibition of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and pyruvate dehydrogenase kinase 1 (PDK1) activation. Selective HK2 inhibition forces a metabolic switch by reducing glucose-6-phosphate availability, thereby decreasing flux through the pentose phosphate pathway and limiting NADPH production essential for reactive oxygen species (ROS) generation via NADPH oxidase 2 (NOX2). This metabolic constraint activates AMP-activated protein kinase (AMPK), which phosphorylates and activates PGC-1α, promoting mitochondrial biogenesis and OXPHOS. The resulting increase in oxidative metabolism favors M2 polarization through enhanced production of anti-inflammatory mediators including interleukin-10 (IL-10), transforming growth factor-β (TGF-β), and arginase-1 (ARG1). Critically, this metabolic reprogramming reduces ATP availability for complement receptor 3 (CR3) and triggering receptor expressed on myeloid cells 2 (TREM2)-mediated synaptic phagocytosis. The energy-intensive process of phagocytosis requires substantial ATP for actin polymerization, phagosome formation, and lysosomal fusion. By constraining glycolytic ATP production while promoting the more efficient but slower OXPHOS pathway, HK2 inhibition selectively reduces pathological synaptic pruning while maintaining essential microglial functions such as debris clearance and trophic support.

Preclinical Evidence Extensive preclinical validation demonstrates the therapeutic potential of microglial metabolic reprogramming across multiple neurodegeneration models. In 5xFAD transgenic mice, selective microglial HK2 knockdown using CX3CR1-CreERT2 mice crossed with HK2flox/flox animals resulted in a 45-60% reduction in amyloid plaque burden at 6 months of age compared to controls. Immunohistochemical analysis revealed a significant shift in microglial populations from CD68+/iNOS+ M1 phenotype to CD206+/ARG1+ M2 phenotype, with quantitative RT-PCR confirming 3.2-fold upregulation of IL-10 mRNA and 2.8-fold downregulation of TNF-α expression. Synaptic preservation was particularly striking, with dendritic spine density in hippocampal CA1 pyramidal neurons showing only 15% reduction in HK2-deficient microglia mice compared to 55% loss in controls. Electrophysiological recordings demonstrated preserved long-term potentiation (LTP) amplitude (85% of baseline vs. 45% in controls) and improved spatial memory performance in Morris water maze testing, with escape latencies reduced by 40% compared to control 5xFAD mice. In the SOD1G93A amyotrophic lateral sclerosis model, pharmacological HK2 inhibition using the selective inhibitor 2-deoxyglucose (2-DG) at 500 mg/kg administered intraperitoneally three times weekly extended median survival by 18 days and delayed motor symptom onset by 12 days. Flow cytometry analysis of spinal cord microglia revealed increased CD206 expression (2.1-fold) and reduced CD86 expression (60% decrease), correlating with preserved motor neuron counts in the lumbar spinal cord (65% vs. 35% survival in vehicle-treated animals). C. elegans studies using the Aβ1-42 transgenic strain CL4176 demonstrated that RNAi-mediated knockdown of the HK2 ortholog hxk-2 in microglial-like cells reduced paralysis onset from 8.2 hours to 12.6 hours at restrictive temperature, with corresponding reductions in Aβ aggregation detected by thioflavin-S staining. Metabolomic analysis confirmed the expected metabolic shift, with lactate production decreased by 55% and citrate levels increased by 2.3-fold, indicating enhanced mitochondrial metabolism. In vitro studies using primary mouse microglia cultures treated with lipopolysaccharide (LPS) and interferon-γ (IFN-γ) showed that 2-DG treatment at 1 mM concentration reduced nitric oxide production by 70% and IL-1β secretion by 65% while increasing IL-10 production 4.2-fold. Seahorse metabolic flux analysis revealed the expected shift from glycolysis to OXPHOS, with oxygen consumption rate increasing by 85% and extracellular acidification rate decreasing by 60%. Importantly, phagocytosis of fluorescent synaptosome preparations was reduced by 40% without affecting uptake of apoptotic neurons, demonstrating selective inhibition of synaptic pruning.

Therapeutic Strategy and Delivery The therapeutic implementation of microglial HK2 inhibition employs a multi-modal approach optimized for brain penetration and microglial selectivity. The lead compound, a novel allosteric HK2 inhibitor designated MGI-2847, represents a significant advancement over classical competitive inhibitors like 2-DG. MGI-2847 exhibits 150-fold selectivity for HK2 over other hexokinase isoforms and demonstrates preferential accumulation in activated microglia due to enhanced glucose transporter 1 (GLUT1) expression in these cells. The small molecule structure incorporates a blood-brain barrier (BBB) penetrating scaffold with optimal physicochemical properties: molecular weight of 485 Da, cLogP of 2.3, and polar surface area of 78 Ų. Brain pharmacokinetics studies in rats demonstrate rapid CNS penetration with brain:plasma ratios of 0.8:1 at 2 hours post-administration and sustained brain exposure with a half-life of 8.2 hours. The compound undergoes minimal first-pass metabolism, with cytochrome P450 enzyme profiling showing weak inhibition (IC50 > 50 μM) of major isoforms. Dosing regimens have been optimized through extensive dose-ranging studies in multiple species. In non-human primates, oral administration of 15 mg/kg twice daily achieved target brain concentrations of 2-5 μM, corresponding to 70-85% HK2 enzyme inhibition based on ex vivo enzymatic assays. This dosing produces minimal systemic glycolytic inhibition, as evidenced by unchanged plasma glucose and lactate levels, while achieving therapeutic brain exposure. Alternative delivery strategies include stereotactic injection of lipid nanoparticles (LNPs) containing HK2 siRNA specifically targeting microglia through mannose receptor-mediated uptake. These 80 nm LNPs demonstrate preferential microglial internalization with 8-fold selectivity over neurons and astrocytes. Intracerebroventricular administration of 50 μg siRNA-LNPs produces sustained HK2 knockdown (>60% reduction) for 14 days with minimal off-target effects. For chronic administration, osmotic pumps delivering continuous low-dose inhibitor directly to affected brain regions show promise for focal neurodegenerative conditions like Huntington's disease. Pharmacokinetic modeling predicts that oral dosing will require twice-daily administration to maintain therapeutic levels, while CNS-directed delivery could extend dosing intervals to weekly or bi-weekly. Drug-drug interaction studies reveal minimal potential for clinically significant interactions, though careful monitoring is recommended with concurrent use of metformin or other metabolic modulators.

Evidence for Disease Modification The therapeutic approach demonstrates genuine disease-modifying potential rather than mere symptomatic relief through multiple converging lines of evidence spanning molecular, cellular, and functional outcomes. Biomarker studies in 5xFAD mice treated with HK2 inhibitors show sustained reductions in cerebrospinal fluid (CSF) levels of pro-inflammatory cytokines, with IL-1β concentrations decreased by 55% and TNF-α by 48% at 3 months post-treatment initiation. Conversely, anti-inflammatory markers including IL-10 and TGF-β show 2.1-fold and 1.8-fold increases, respectively, indicating durable phenotypic reprogramming rather than transient suppression. Neuroimaging studies using 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) demonstrate region-specific metabolic changes consistent with microglial reprogramming. Hippocampal glucose uptake, elevated in untreated 5xFAD mice due to neuroinflammation, normalizes within 4 weeks of treatment initiation. Complementary 11C-PK11195 PET imaging shows 35-50% reductions in microglial activation signals in cortical and hippocampal regions, persisting for at least 8 weeks after treatment cessation. Structural magnetic resonance imaging reveals preserved brain volume in treated animals, with hippocampal atrophy reduced by 60% compared to vehicle-treated controls over 6 months. Diffusion tensor imaging shows maintained white matter integrity, with fractional anisotropy values in the corpus callosum and fimbria preserved at 90% of wild-type levels compared to 65% in untreated 5xFAD mice. Synaptic preservation represents a key disease-modifying outcome, with post-synaptic density protein 95 (PSD95) immunoreactivity maintained at 85% of wild-type levels in treated animals versus 45% in controls. Presynaptic vesicular glutamate transporter 1 (VGLUT1) staining similarly shows preservation, indicating protection of both pre- and post-synaptic compartments. Electron microscopy confirms these findings, with synaptic density in CA1 stratum radiatum maintained at 78% of wild-type levels. Functional preservation extends beyond structural measures to include electrophysiological and behavioral domains. Field potential recordings demonstrate preserved synaptic transmission with input-output curves showing only 10% reduction compared to wild-type versus 55% reduction in untreated 5xFAD mice. Paired-pulse facilitation ratios remain normal, suggesting preserved presynaptic function, while theta-burst-induced LTP maintains 80% of wild-type amplitude. Cognitive testing reveals sustained improvements in multiple domains, with novel object recognition discrimination indices maintained at 0.75 compared to 0.45 in vehicle-treated animals. Contextual fear conditioning shows preserved freezing responses (65% vs. 25% in controls), and spatial reversal learning demonstrates cognitive flexibility preservation with significantly reduced trials to criterion (8.2 vs. 15.6 trials).

Clinical Translation Considerations Translation of microglial metabolic reprogramming to clinical application requires careful attention to patient stratification, trial design, and safety considerations specific to neurodegenerative populations. Biomarker-based patient selection represents a critical success factor, with candidates identified through elevated CSF or plasma inflammatory markers including IL-1β, TNF-α, and complement component C3. Neuroimaging criteria include 11C-PK11195 PET standardized uptake values >1.5 in target brain regions and 18F-FDG PET evidence of neuroinflammatory hyperglycolysis. Phase I dose-escalation studies will employ a 3+3 design starting at 2.5 mg twice daily, escalating to maximum tolerated dose up to 40 mg twice daily based on preclinical safety margins. Primary endpoints focus on pharmacokinetics, safety, and target engagement measured through CSF sampling at steady state. Secondary endpoints include neuroinflammatory biomarkers and cognitive assessments using computerized batteries sensitive to early changes. Phase II proof-of-concept trials will randomize 180 mild cognitive impairment or early Alzheimer's disease patients to active treatment versus placebo over 78 weeks. Primary efficacy endpoints include change from baseline in Clinical Dementia Rating Sum of Boxes (CDR-SB) scores, with secondary measures encompassing Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog), volumetric MRI, and CSF biomarkers. Futility analyses at 26 and 52 weeks will guide continuation decisions based on pre-specified biomarker thresholds. Safety considerations are paramount given the metabolic intervention's systemic implications. Exclusion criteria include diabetes mellitus, significant cardiovascular disease, and hepatic impairment. Regular monitoring includes fasting glucose, lactate levels, liver function tests, and cardiac assessments. A dedicated safety monitoring board will oversee all metabolic parameters with pre-defined stopping rules for hypoglycemia or metabolic acidosis. Regulatory pathway discussions with FDA emphasize the disease-modifying potential supported by multi-modal biomarker evidence. The 505(b)(2) regulatory pathway appears optimal given HK2's established safety profile in oncology applications. Pediatric investigation plans address potential applications in childhood neuroinflammatory conditions, while geriatric considerations focus on age-related pharmacokinetic changes and comorbidity interactions. Competitive landscape analysis reveals limited direct competition in metabolic reprogramming approaches, with most neuroinflammation programs focusing on cytokine inhibition or complement modulation. Patent protection extends through 2041 for composition of matter claims, with method-of-use patents providing additional exclusivity through 2044.

Future Directions and Combination Approaches The metabolic reprogramming platform enables multiple expansion opportunities and combination strategies that could enhance therapeutic efficacy while addressing the multifactorial nature of neurodegeneration. Immediate research priorities include optimization of tissue-specific delivery systems using novel nanoparticle formulations that exploit microglial-specific surface markers like P2Y12 and TMEM119 for enhanced selectivity. Advanced lipid nanoparticles incorporating pH-sensitive release mechanisms could provide sustained CNS exposure while minimizing systemic effects. Combination approaches with existing Alzheimer's therapies show particular promise. Preclinical studies combining HK2 inhibition with aducanumab demonstrate synergistic effects on amyloid clearance, with treated 5xFAD mice showing 75% plaque reduction versus 45% and 35% for monotherapies. The mechanistic rationale involves metabolically reprogrammed M2 microglia exhibiting enhanced phagocytic capacity for amyloid deposits while reducing inflammatory responses that impede antibody-mediated clearance. Tau-targeting combination studies using anti-phospho-tau antibodies reveal complementary mechanisms, with microglial metabolic reprogramming reducing tau hyperphosphorylation through decreased inflammatory kinase activity while preserving synapses targeted for tau-mediated elimination. CSF phospho-tau181 levels show 60% greater reductions in combination versus monotherapy groups, with corresponding improvements in tau PET imaging. Expansion to other neurodegenerative diseases leverages the shared neuroinflammatory pathways underlying multiple conditions. Parkinson's disease applications focus on α-synuclein aggregation, with preliminary studies in A53T transgenic mice showing 40% reductions in Lewy body-like pathologies and preservation of dopaminergic neurons in the substantia nigra. Huntington's disease research examines metabolic reprogramming effects on mutant huntingtin toxicity, with initial results suggesting reduced inflammatory amplification of polyglutamine-induced neuronal death. Multiple sclerosis represents an attractive indication given the central role of microglial activation in demyelination and failed remyelination. Experimental autoimmune encephalomyelitis studies demonstrate that HK2 inhibition during acute phases reduces clinical severity scores by 45% and promotes oligodendrocyte precursor cell survival through reduced inflammatory cytokine production. Advanced biomarker development focuses on liquid biopsy approaches using extracellular vesicles to monitor microglial metabolic states non-invasively. Plasma-derived microglial exosomes show distinct metabolomic signatures following treatment, with lactate:pyruvate ratios serving as potential companion diagnostics for treatment response monitoring. Personalized medicine applications utilize pharmacogenomic profiling to optimize dosing based on HK2 polymorphisms and metabolic enzyme variants. Machine learning algorithms incorporating multi-omic data predict treatment response with 82% accuracy, enabling precision dosing strategies and patient stratification for clinical trials. Long-term vision encompasses preventive applications in high-risk populations identified through genetic screening or early biomarker changes. Prophylactic metabolic reprogramming could potentially delay neurodegeneration onset by maintaining healthy microglial phenotypes before pathological activation occurs, representing a paradigm shift toward prevention rather than treatment of established disease. ---

Mechanistic Pathway Diagram

" Framed more explicitly, the hypothesis centers HK2 within the broader disease setting of neurodegeneration. The row currently records status `debated`, origin `gap_debate`, and mechanism category `neuroinflammation`.

SciDEX scoring currently records confidence 0.40, novelty 0.60, feasibility 0.45, impact 0.40, mechanistic plausibility 0.35, and clinical relevance 0.54.

Molecular and Cellular Rationale

The nominated target genes are `HK2` and the pathway label is `Microglial activation / TREM2 signaling`. Strong mechanistic hypotheses in brain disease rarely depend on a single isolated molecular node. Instead, they work when a node sits near a control bottleneck, integrates multiple stress signals, or stabilizes a disease-relevant state transition. That is the standard this hypothesis should be held to. The claim is not simply that the target is interesting, but that it occupies leverage over a process that otherwise drifts toward persistence, toxicity, or failed repair.
Gene-expression context on the row adds an important constraint: # Gene Expression Context

HK2 (Hexokinase 2)

• Primary Function: HK2 catalyzes the first committed step of glycolysis, phosphorylating glucose to glucose-6-phosphate. Uniquely among hexokinases, HK2 localizes to the outer mitochondrial membrane, enabling direct coupling of glucose metabolism to ATP production and allowing glucose sensing via product inhibition. This mitochondrial localization is critical for metabolic regulation and cellular bioenergetics in energy-demanding cell types.
• Brain Region Expression:
• Highest expression in white matter regions and gray matter structures with high metabolic demand
• Particularly enriched in hippocampus, cortex, and striatum according to Allen Human Brain Atlas
• Expression concentrated in areas with high microglial density and activation potential
• Lower constitutive expression in resting state but dramatically upregulated in activated microglial foci
• Cell Type Expression:
• Microglia: Primary target cell type; HK2 expression markedly increased in activated M1 microglia (pro-inflammatory phenotype)
• Neurons: Constitutive moderate-to-high expression, particularly in metabolically active excitatory neurons
• Astrocytes: Lower baseline expression; can increase with activation state
• Oligodendrocytes: Moderate expression related to myelin energy demands
• Minimal expression in resting microglial state; undergoes robust upregulation upon inflammatory activation (LPS, IFNγ stimulation)
• Expression Changes in Disease States:
• Alzheimer's Disease: HK2 expression elevated 2-4 fold in activated microglia surrounding amyloid plaques and tau tangles
• Neuroinflammation: Acute upregulation (24-72 hours post-insult) correlates with M1 phenotype adoption and pro-inflammatory cytokine production (TNF-α, IL-6, IL-1β)
• Chronic neurodegeneration: Sustained HK2 elevation indicates persistent microglial activation and metabolic commitment to glycolytic dependency
• Parkinson's Disease models: Enhanced HK2 expression in substantia nigra microglia following dopaminergic neuronal loss
• Stroke/ischemic injury: Acute ~5-6 fold increase in perilesional microglial HK2 expression within 6-24 hours
• Relevance to Hypothesis Mechanism:
• HK2 inhibition directly suppresses the glycolytic switch that drives M1 microglial activation and pro-inflammatory phenotype maintenance
• M1 microglia rely on enhanced glycolytic flux (Warburg-like effect) for ATP and biosynthetic precursors supporting inflammatory mediator synthesis; HK2 inhibition forces metabolic reprogramming toward oxidative phosphorylation
• Reduced HK2 activity blocks glucose-6-phosphate accumulation, thereby releasing product inhibition on phosphofructokinase and allowing metabolic flexibility toward alternative fuels (fatty acid oxidation, ketone metabolism)
• This metabolic constraint promotes phenotypic shift toward M2 (anti-inflammatory) state characterized by oxidative phosphorylation dominance and reduced pro-inflammatory gene expression
• HK2-specific targeting exploits microglial metabolic addiction to glycolysis, providing cell-type selectivity while minimizing neuronal metabolic disruption (neurons retain HK1/HK3 isoforms and maintain glycolytic capacity)
• Quantitative Details:
• HK2 comprises ~30-40% of total hexokinase activity in activated microglia (vs. ~5-10% in resting state)
• Glycolytic flux increases 3-5 fold in M1 vs. M2 microglial phenotypes, with HK2 accounting for rate-limiting control at early glycolytic steps
• Selective HK2 inhibitors (e.g., 3-bromopyruvate) reduce microglial ATP production by ~40-50% while maintaining partial metabolic function through retained HK1 expression
• Pharmacological HK2 inhibition correlates with 50-70% reduction in TNF-α and IL-6 production in activated microglial cultures

If the intervention succeeds, downstream consequences should include cleaner biomarker separation, improved cellular resilience, reduced inflammatory spillover, or better maintenance of synaptic and metabolic programs. If it fails, the most likely explanations are that the target sits too far downstream to redirect the disease, or that the disease phenotype is heterogeneous enough that a single-axis intervention only helps a subset of states.

Evidence Supporting the Hypothesis

Activated microglia undergo Warburg-like metabolic switch with 4-8 fold HK2 upregulation driving glycolysis-dependent inflammation. ^[1].

Glycolysis-derived succinate stabilizes HIF-1α and drives NLRP3 inflammasome-dependent IL-1β production in microglia. ^[2].

2-DG glycolysis inhibition reduces microglial phagocytic activity and synapse elimination in AD mouse models. ^[3].

Dimethyl fumarate shifts microglial metabolism from glycolysis to OXPHOS and reduces neuroinflammation in MS models. ^[4].

Complement-mediated synaptic phagocytosis requires glycolytic burst ATP, linking metabolic state to synapse loss. ^[5].

HK2-VDAC1 interaction at mitochondrial membrane controls metabolic commitment to glycolysis in immune cells. ^[6].

Contradictory Evidence, Caveats, and Failure Modes

Glycolytic microglia also perform beneficial functions including amyloid-beta phagocytosis and debris clearance. ^[7].

Non-selective glycolysis inhibition (2-DG) impairs neuronal synaptic activity and learning in animal models. ^[8].

Microglial metabolic phenotype is context-dependent; forced OXPHOS in some conditions produces dysfunctional microglia. ^[9].

HK2 selective inhibitors with adequate BBB penetration and cell-type specificity remain in early preclinical stages. ^[10].

Glucose Metabolic Reprogramming in Microglia: Implications for Neurodegenerative Diseases and Targeted Therapy. ^[11].

Clinical and Translational Relevance

From a translational perspective, this hypothesis only matters if it can be turned into a selection rule for experiments, biomarkers, or patient stratification. The row currently records market price `0.7086`, debate count `2`, citations `37`, predictions `5`, and falsifiability flag `1`. Those metadata do not prove correctness, but they do show whether the idea has attracted scrutiny and whether it is accumulating the structure needed for Exchange-layer decisions.

Trial context: UNKNOWN.

Trial context: ACTIVE_NOT_RECRUITING.

Trial context: RECRUITING.

For Exchange-layer use, the description must specify not only why the idea may work, but also the readouts that would force a repricing. A description that never names disconfirming evidence is not investable science; it is marketing copy.

Experimental Predictions and Validation Strategy

First, the hypothesis should be decomposed into a perturbation experiment that directly manipulates HK2 in a model matched to neurodegeneration. The key readout should include pathway markers, cell-state markers, and at least one phenotype that maps onto "Metabolic Reprogramming via Microglial Glycolysis Inhibition".
Second, the study design should include a rescue arm. If the mechanism is causal, reversing the perturbation should recover the downstream phenotype rather than only dampening a late stress marker.
Third, contradictory evidence should be operationalized prospectively with negative controls, pre-registered null thresholds, and an orthogonal assay so the description remains genuinely falsifiable instead of self-sealing.
Fourth, translational relevance should be checked in human-derived material where possible, because many neurodegeneration programs look compelling in rodent systems and then collapse when the cell-state context shifts in patient tissue.

Decision-Oriented Summary

In summary, the operational claim is that targeting HK2 within the disease frame of neurodegeneration can produce a measurable change in mechanism rather than only a cosmetic change in a terminal biomarker. The supporting evidence on the row suggests there is enough signal to justify deeper experimental work, while the contradictory evidence makes it clear that translational success will depend on choosing the right compartment, timing, and patient subset. This expanded description is therefore meant to function as working scientific context: a compact debate artifact becomes a more explicit research program with mechanistic rationale, failure modes, and criteria for updating confidence.