  Hyperluminous quasars ($L_{\rm bol}\gtrsim 10^{47}$ erg s$^{-1}$) are ideal
laboratories to study the interaction and impact of extreme radiative field and
the most powerful winds in the AGN nuclear regions. They typically exhibit low
coronal X-ray luminosity ($L_{\rm X}$) compared to the UV and MIR radiative
outputs ($L_{\rm UV}$ and $L_{\rm MIR}$) with a non-negligible fraction of them
reporting even $\sim$1 dex weaker $L_{\rm X}$ compared to the prediction of the
well established $L_{\rm X}$-$L_{\rm UV}$ and $L_{\rm X}$-$L_{\rm MIR}$
relations followed by the bulk of the AGN population. We report in our
WISE/SDSS-selected Hyperluminous (WISSH) $z=2-4$ broad-line quasar sample, the
discovery of a dependence between the intrinsic 2-10 keV luminosity ($L_{\rm
2-10}$) and the blueshifted velocity of the CIV emission line ($v_{\rm CIV}$)
indicative of accretion disc winds. In particular, sources with fastest winds
($v_{\rm CIV}\gtrsim 3000~\rm km s^{-1}$) possess $\sim$0.5-1 dex lower $L_{\rm
2-10}$ than sources with negligible $v_{\rm CIV}$. No similar dependence is
found on $L_{\rm UV}$, $L_{\rm MIR}$, $L_{\rm bol}$, photon index and
absorption column density. We interpret these findings in the context of
accretion disc wind models. Both magnetohydrodynamic and line-driven models can
qualitatively explain the reported relations as a consequence of X-ray
shielding from the inner wind regions. In case of line-driven winds, the launch
of fast winds is favoured by a reduced X-ray emission, and we speculate that
these winds may play a role in directly limiting the coronal hard X-ray
production.
