Michael David Forrest

IF1 protein inhibits F ₁ F ₀ ATP hydrolysis (and not F ₁ F ₀ ATP synthesis). Across investigated species more IF1 protein, and less F ₁ F ₀ ATP hydrolysis, correlates with greater maximal lifespan. Increased IF1 protein, and decreased F ₁ F ₀ ATP hydrolysis, safely reduces a biomarker of aging in mice. Body temperature decrease, in mice administered with a small molecule drug that selectively inhibits F ₁ F ₀ ATP hydrolysis (which doesn’t inhibit F ₁ F ₀ ATP synthesis), is evidence that F ₁ F ₀ ATP hydrolysis is used for metabolic heat generation in vivo . Instrumental to homeothermy, which is a new fundamental discovery. A further discovery is that cancer cells subvert F ₁ F ₀ ATP hydrolysis to drive their distinctive Warburg metabolism and so selective drug inhibition of F ₁ F ₀ ATP hydrolysis exerts potent anticancer activity. When the body is in an ambient temperature of 37°C (or more), no metabolic heat generation is needed for the body to be at 37°C, and so a large dose of a F ₁ F ₀ ATP hydrolysis inhibiting anticancer drug may be administered, which may slow aging. So, here might be an entirely new class of anticancer drugs that may (when appropriately used) help, instead of harm, normal cells. Distinct from present anticancer drugs, which greatly harm normal cells, causing horrific side-effects, which kill many and cause many others to abandon cancer treatment. In short, this paper teaches how mammals metabolically generate heat, why different mammal species have different maximal lifespans, and new anticancer drugs, that are predicted to slow aging. SIGNIFICANCE: Has nature taught us how to slow aging? Different mammal species age at different rates, conferring different maximal lifespans. For example, the maximal lifespan of a mouse is 4 years, while that of a bowhead whale is 211 years. So, aging is modifiable. But how? A clue might be body size: smaller mammal species tend to age faster than larger ones. In geometry, by its square-cube law, smaller objects have a greater surface-area to volume ratio than larger objects. Meaning smaller mammal species more readily lose their metabolically generated heat. And so, per unit time, each gram of a smaller mammal species needs to generate more metabolic heat than each gram of a larger mammal species, to keep their body temperature around 37°C. The chemical reactions that the body uses to obtain energy from food (e.g., to keep the body warm) produce harmful by-products: Reactive Oxygen Species (ROS), which cause molecular damage. The accumulation of which might be aging. Per unit time, each gram of a smaller mammal species generates more metabolic heat, uses more food, produces more ROS, and ages more. Newly reported herein is a chemical reaction that homeotherms use to generate heat (F ₁ F ₀ ATP hydrolysis). By the 2 ^nd Law of Thermodynamics, whenever energy converts from one form to another, some of this energy must be dissipated as heat (no energy conversion can be 100% efficient). I’ve discovered, in homeotherms, ATP synthase enzyme hydrolyses some of the ATP it synthesizes (i.e., performs F ₁ F ₀ ATP hydrolysis). Causing futile cycling between ATP synthesis and ATP hydrolysis, conditional upon passing and pumping protons along a concentration gradient respectively. So, cyclically interconverting between potential and chemical energies, which (by the inefficiency of energy conversions) generates heat to maintain body temperature. Across a set of mammal species: per unit time, each gram of smaller (shorter-living) mammal species do more of this heat generating reaction (F ₁ F ₀ ATP hydrolysis) than each gram of larger (longer-living) mammal species. Because they have less IF1 protein (activity per unit mass), where IF1 protein selectively inhibits F ₁ F ₀ ATP hydrolysis ( doesn’t inhibit F ₁ F ₀ ATP synthesis ). Across these mammal species, maximal lifespan is inversely proportional to the use (per unit time per unit mass) of F ₁ F ₀ ATP hydrolysis. That drives the inverse proportionality between metabolic rate per unit mass and maximal lifespan, which causes the inverse proportionality between heart rate and maximal lifespan, observed across these mammal species. Increased IF1 protein, and decreased F ₁ F ₀ ATP hydrolysis, safely reduces a biomarker of aging in mice. So, correlational and interventional data. My interpretation of data herein is that different mammal species have different maximal lifespans because of different IF1 protein activity (per unit mass). Where more IF1 protein activity (per unit mass) confers longer lifespan. A small-molecule drug that selectively inhibits F ₁ F ₀ ATP hydrolysis, which doesn’t inhibit F ₁ F ₀ ATP synthesis, is shown to dose-dependently reduce metabolic heat generation (and metabolic rate thereby) in mice. Higher dose reduces it more. Such a drug is predicted to slow aging. Indeed, its mechanism of action (selectively inhibiting F ₁ F ₀ ATP hydrolysis) is shown to safely decrease intracellular ROS concentration in mice. Less metabolic heat generation doesn’t necessarily mean lower body temperature. Body temperature can be the same with less metabolic heat generation by proportionally greater body insulation, such as wearing more or better clothing, and/or a conducive ambient temperature. A human, in typical clothing, is most comfortable at an ambient temperature around 20.3°C. But much of the world is hotter, at least for part of the year, especially when close to the equator (43% of the world’s population lives in the tropics). Such a drug might, by dose-dependently reducing metabolic heat generation, increase thermal comfort in hot places, possibly slowing aging. To illustrate: a relatively small drug dose might increase a clothed person’s preferred ambient temperature to 23°C, a higher dose to 27°C, an even higher dose to 32°C, and so on. When metabolic heat generation is low, the preferred ambient temperature is close to 37°C. When the ambient temperature is 37°C or more, no metabolic heat generation is needed for the body to be at 37°C. I predict when such a drug is applied topically to a small body part, such as to the face in a cosmetic cream, it will reduce metabolic heat generation at that location, reducing metabolic rate and thereby slow aging there. Wherein heat transfer from the rest of the body, via blood flow, maintains this body part at around 37°C, because topical use can’t reduce body temperature at any ambient temperature. Less F ₁ F ₀ ATP hydrolysis, enough predicted to slow aging by two-thirds, has been proven safe in mice, at least when localized to a body part. Slowing the aging of even just a small part of the body has cosmetic and - because many diseases of aging are highly localized ( for example, to the eyes: e.g., Age-Related Macular Degeneration ) - medical applications. Probably the incidence and progression of age-related diseases correlates with age/aging because aging is causal to them, and so a single drug that slows aging might confer therapeutic benefit for many, varied diseases of aging. Such diseases must be beaten to avert the otherwise coming demographic/economic crisis in which too much of the population suffers, and is debilitated by, at least one of them. A drug to slow aging is a desperate want and has been since the dawn of mankind. GRAPHICAL

I use the Nernst equation, parameterised with experimental data, to predict that cancer cells will accumulate more of a lipophilic anion than normal cells. This effect is correlated to charge number. Model cancer cells accumulate *100 more of an anion, *10³more di-anion, *10⁶more tri-anion, *10⁸more tetra-anion and *10¹⁰more penta-anion (>>1 billion times more). The trend endures, conveying even greater specificity, for higher charge numbers. This effect could be leveraged for cancer therapy. Wherein the lipophilic anion is a toxin that targets some vital cellular process, which normal and cancer cells may even share. It delivers a high, lethal dose to cancer cells but a low, safe dose to normal cells. This mathematical finding conveys the prospect of a broad, powerful new front against cancer.

Cancer cells have a more hyperpolarised mitochondrial membrane potential (Ψ _IM ) than normal cells. Ψ _IM = ∼−220 mV in cancer cells as compared to ∼−140 mV in normal cells. Until now it has not been known why. This paper explains this disparity, in a mathematical framework, and identifies molecular targets and operations unique to cancer cells. These are thence prospective cancer drug targets. BMS-199264 is proposed as an anti-cancer drug. It inhibits the reverse, proton-pumping mode of ATP synthase, which this paper identifies as crucial to cancer cells but not to healthy, normal adult cells. In the cancer cell model, the adenine nucleotide exchanger (ANT) is inversely orientated in the mitochondrial inner membrane as compared to normal cells. This predicts it to have a different drug interaction profile, which can be leveraged for cancer therapy. Uncouplers, which dissipate the proton motive force, are proposed as anti-cancer medicines e.g. 2,4-dinitrophenol.

We propose that NADH will exert a specific kill action against some cancers. NADH is a natural metabolite. We envisage a low side effect profile and that NADH therapy will, additionally, combat the wastage and weakness of cancer patients, which can be the cause of death in some cases. Significantly, NADH can be administered orally and has already cleared clinical trials, all be it for other pathologies. Background: Aerobic respiration consists of glycolysis in the cytoplasm and in the mitochondria: the Krebs cycle and oxidative phosphorylation (OXPHOS) [1, 2]. It requires O ₂ and net yields 30 ATPs from one glucose molecule. Anaerobic respiration, consisting of glycolysis only, does not require O ₂ but produces merely 2 ATPs from one glucose molecule. When O ₂ is available, normal animal cells tend to favour aerobic respiration because of its higher ATP yield.

An approach to investigate brain function/dysfunction is to simulate neuron circuits on a computer. A problem, however, is that detailed neuron descriptions are computationally expensive and this handicaps the pursuit of realistic network investigations, where many neurons need to be simulated. We confront this issue; we employ a novel reduction algorithm to produce a 2 compartment model of the cerebellar Purkinje neuron from a previously published, 1089 compartment model. It runs more than 400 times faster and retains the electrical behavior of the full model. So, it is more suitable for inclusion in large network models, where computational power is a limiting issue. We show the utility of this reduced model by demonstrating that it can replicate the full model’s response to alcohol, which can in turn reproduce experimental recordings from Purkinje neurons following alcohol application. We show that alcohol may modulate Purkinje neuron firing by an inhibition of their sodium-potassium pumps. We suggest that this action, upon cerebellar Purkinje neurons, is how alcohol ingestion can corrupt motor co-ordination. In this way, we relate events on the molecular scale to the level of behavior.

The sodium-potassium pump is an information processing element in brain computation

Without synaptic input, Purkinje neurons can spontaneously fire in a repeating trimodal pattern that consists of tonic spiking, bursting and quiescence. Climbing fiber input (CF) switches Purkinje neurons out of the trimodal firing pattern and toggles them between a tonic firing and a quiescent state, while setting the gain of their response to Parallel Fiber (PF) input. The basis to this transition is unclear. We investigate it using a biophysical Purkinje cell model under conditions of CF and PF input. The model can replicate these toggle and gain functions, dependent upon a novel account of intracellular calcium dynamics that we hypothesise to be applicable in real Purkinje cells.

Hodgkin and Huxley (H-H) fitted their model of voltage-dependent conductances to experimental data using empirical functions of voltage. The thermodynamic H-H model of voltage dependent conductances is more physically plausible, as it constrains and parameterises its empirical fit by assuming that ion channel transition rates depend exponentially on a free energy barrier that in turn, linearly or non-linearly, depends on voltage. The original H-H model contains no explicit temperature terms and requires Q₁₀ factors to describe data at different temperatures. The thermodynamic H-H model does have explicit terms for temperature. Do these endow the model with extrapolation for temperature? We utilised voltage clamp data for a voltage-gated K⁺ current, recorded at three different temperatures. The thermodynamic H-H model’s free parameters were fitted (Marquardt-Levenberg algorithm) to a data set recorded at one (or more) temperature(s). Then we assessed whether it could describe another data set, recorded at a different temperature, with these same free parameter values and its temperature terms set to the new temperature. We found that it could not.

In vitro, Purkinje cell behaviour is sometimes studied in a dissociated soma preparation in which the dendritic projection has been cleaved. A fraction of these dissociated somas spontaneously burst. The mechanism of this bursting is incompletely understood. We have constructed a biophysical Purkinje soma model, guided and constrained by experimental reports in the literature, that can replicate the somatically driven bursting pattern and which hypothesises Persistent Na⁺ current (I_NaP) to be its burst initiator and SK K⁺ current (I_SK) to be its burst terminator.

In vitro, cerebellar Purkinje cells can intrinsically fire action potentials in a repeating trimodal or bimodal pattern. The trimodal pattern consists of tonic spiking, bursting, and quiescence. The bimodal pattern consists of tonic spiking and quiescence. It is unclear how these firing patterns are generated and what determines which firing pattern is selected. We have constructed a realistic biophysical Purkinje cell model that can replicate these patterns. In this model, Na⁺/K⁺ pump activity sets the Purkinje cell's operating mode. From rat cerebellar slices we present Purkinje whole cell recordings in the presence of ouabain, which irreversibly blocks the Na⁺/K⁺ pump. The model can replicate these recordings. We propose that Na⁺/K⁺ pump activity controls the intrinsic firing mode of cerbellar Purkinje cells.